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ORIGINAL PAPER
Bargaining and the provision of health services
Luigi Siciliani • Anderson Stanciole
Received: 22 July 2010 / Accepted: 8 February 2012 / Published online: 16 March 2012
� Springer-Verlag 2012
Abstract We model and compare the bargaining process
between a purchaser of health services, such as a health
authority, and a provider (the hospital) in three plausible
scenarios: (a) activity bargaining: the purchaser sets the
price and activity (number of patients treated) is bargained
between the purchaser and the provider; (b) price bar-
gaining: the price is bargained between the purchaser and
the provider, but activity is chosen unilaterally by the
provider; (c) efficient bargaining: price and activity are
simultaneously bargained between the purchaser and the
provider. We show that: (1) if the bargaining power of the
purchaser is high (low), efficient bargaining leads to higher
(lower) activity and purchaser’s utility, and lower (higher)
prices and provider’s utility compared to price bargaining.
(2) In activity bargaining, prices are lowest, the purchaser’s
utility is highest and the provider’s utility is lowest; activity
is generally lowest, but higher than in price bargaining for
high bargaining power of the purchaser. (3) If the purchaser
has higher bargaining power, this reduces prices and
activity in price bargaining, it reduces prices but increases
activity in activity bargaining, and it reduces prices but has
no effect on activity in efficient bargaining.
Keywords Bargaining � Negotiation � Purchasing
JEL Classification I11
Introduction
Prospective payment systems are used widely to remu-
nerate health care providers. In the hospital sector, they
usually take the form of Diagnosis Related Groups (DRGs)
pricing or similar methods, such as Healthcare Resource
Groups (HRGs) in the United Kingdom or Group Hom-
ogenes de Maladie (GMC) in France. Depending on the
institutional context, purchasers and providers (i.e. hospi-
tals) bargain on price, activity (i.e. numbers of patients
treated), or both. For example, in the US, Health care
Maintenance Organisations (HMOs) or private health
insurers bargain with hospitals on price, and seldom the
number of patients treated, i.e. activity [2, 6]. In the United
Kingdom, public purchasers (i.e. Health Authorities and
Primary Care Trusts) have been negotiating price and
number of patients treated (i.e. activity) with hospitals
(known in England as NHS Trusts) under ‘‘cost and vol-
ume’’ or ‘‘sophisticated’’ contracts. The government has in
more recent years implemented a policy known as ‘‘Pay-
ment by Results’’, where prices are regulated, but activity
is negotiated between the purchaser (i.e. the Primary Care
Trust) and the hospital (i.e. the NHS Trust). In the future,
Electronic supplementary material The online version of thisarticle (doi:10.1007/s10198-012-0383-x) contains supplementarymaterial, which is available to authorized users.
Anderson Stanciole: Work undertaken while at the University of
York.
L. Siciliani
Department of Economics and Related Studies,
and Centre for Health Economics,
University of York, York, UK
e-mail: [email protected]
L. Siciliani
Centre For Economic Policy Research (C.E.R.P.),
90–98 Goswell Street, London EC1V 7DB, UK
Present Address:A. Stanciole (&)
World Bank, Health, Nutrition, and Population,
1818 H St NW, Washington, DC 20433, USA
e-mail: [email protected]
123
Eur J Health Econ (2013) 14:391–406
DOI 10.1007/s10198-012-0383-x
prices may be allowed to vary again. Within the Medicare
Programme in the US, prices are nominally chosen by the
purchaser (the government), while activity is either chosen
or bargained with the provider: the price decided by the
government could be seen as the outcome of a bargaining
process between the government and the hospital associa-
tion. Similar arrangements exist throughout Europe
[15, pp. 243–245, 20, ch. 1].
Although we observe a substantial amount of bargaining
between purchasers and providers, the theoretical literature
on the relative merits of hospital prospective payment
systems normally assumes that payers are able to set the
prices unilaterally, while hospitals choose the amount of
quality and cost-containment effort, and in cases the
number of patients treated (see, for example, [8, 9, 11, 21,
25, 26, 34]). This implies that purchasers have all the
bargaining power, which is a simplifying assumption, as
the empirical evidence suggests that providers may hold at
least some of it. Propper [32] shows that, in England,
purchasers with higher bargaining power could secure
lower prices. Brooks et al. [6] estimate that US hospitals
hold on average 65% of the bargaining power when
negotiating with private insurers. Melnick et al. [24] find a
negative association between purchasers with greater
market shares and prices charged by the providers.
This study models the bargaining process between a
purchaser of health services (a public or private insurer)
and a provider (a hospital) in three plausible institutional
settings. Under these three settings we always refer, for
short, to ‘‘activity’’ as the total number of patients treated
by a representative hospital. We refer to the ‘‘price’’ as the
monetary converter which translates a DRG with a weight
equal to one into money (US dollars, British pounds, etc):
(a) the purchaser sets the price (stage 1), and the activity
is bargained between the purchaser and the provider
(stage 2): activity bargaining. This scenario corre-
sponds for example to the current arrangements under
‘‘Payment by Results’’ in England. The government
sets the price, but the activity is negotiated between
the Primary Care Trust and the hospital.
(b) The price is bargained between the purchaser and the
provider (stage 1), and the activity is chosen unilat-
erally by the provider (stage 2): price bargaining. This
scenario corresponds for example to the case of an
HMO, which bargains on the price with the hospital,
but the activity (i.e. patients treated) is chosen by the
hospital. This model could also be applied to Medicare
if we interpret the price set by the government each
year to pay hospitals as the result of the negotiations
between Medicare and a hospital association. In
England, the government has recently discussed the
possibility of moving to a setting where the prices is
negotiated between individual hospitals and local
purchasers, on the grounds that this may reflect more
accurately the costs of the hospital (though ultimately
it was not adopted).
(c) Price and activity are bargained simultaneously
between the purchaser and the provider: efficient
bargaining. This scenario corresponds for example to
the old arrangements in England under ‘‘cost and
volume’’ or ‘‘sophisticated’’ contracts’’ where Health
Authorities and Primary Care Trusts have been
negotiating price and number of patients treated (i.e.
activity) with hospitals.
The first two models (activity and price bargaining) are
two-stage models. For both models, prices are decided
before activity takes place. This is a reasonable assump-
tion. Prices are normally set at the beginning of each fiscal
year, before the hospitals start to treat the patients. In the
third model (efficient bargaining), both prices and activity
are decided at the beginning of the financial year, and the
model has then one stage only. Our main objective is to
compare prices, activity and the utility of provider and
purchaser in each of the three different institutional set-
tings. We obtain the following key results.
The key result from the analysis is that if purchasers can
set prices (activity bargaining), purchaser’ utility, which is
given by the net consumer welfare (patient benefit, net of
transfer to the provider), is highest. This result holds for
any level of bargaining power of the purchaser. The anal-
ysis therefore supports policies such as ‘‘payment by
results’’ in the UK or DRG type of payments across Eur-
ope, where prices are fixed by the purchaser or the regu-
lator. This result holds despite the fact that total surplus, i.e.
the sum of purchaser’s and provider’s utility, is not maxi-
mised (the surplus is instead highest under efficient
bargaining).
A second key analytical result is that if the bargaining
power of the purchaser is low, efficient bargaining leads to
higher prices and provider’s utility, and lower activity and
purchaser’s utility, compared to price bargaining. This
result seems surprising, as one would expect the purchaser
to be better off when she can bargain with more instru-
ments, i.e. both price and activity. However, this intuition
holds true only if the bargaining power of the purchaser is
high. If her bargaining power is low, having more instru-
ments is counterproductive. One policy implication is that
purchasers with low bargaining power may be better off if
restricted to bargaining on prices only, and not on price and
activity.
A third counter-intuitive result, which may be important
for policy, is that by shifting from efficient and price bar-
gaining (as in ‘‘cost and volume’’ or ‘‘sophisticated’’ con-
tracts) to activity bargaining (as in ‘‘payment by results’’),
392 L. Siciliani, A. Stanciole
123
the level of activity is likely to decrease. More precisely,
this study predicts that moving from efficient to activity
bargaining will certainly reduce activity. This is in contrast
to what is normally thought, i.e. that ‘‘payment by results’’
will encourage activity. When moving from price to
activity bargaining, activity will decrease (increase) if the
bargaining power of the purchaser is low (high). These
results are consistent with recent empirical evidence [14]
which shows that the introduction of ‘‘payment by results’’
in England did not lead to any significant increase in
activity.
This study contributes to the literature on purchaser-
provider bargaining in healthcare (see [2], for a survey).
Ellis and McGuire [13] develop a model in which patients
and doctors bargain about the intensity of treatment, and
derive the optimal combination of patient’s insurance and
reimbursement for the provider which maximises consumer
welfare.1 The focus is on deriving the intensity of treatment
under different demand and supply side arrangements.
There is no comparison with other types of bargaining.
Barros and Martinez-Giralt [3] show that, when bargaining
with providers, purchasers may prefer to bargain with a
professional association rather than a subset of more effi-
cient providers. They focus on price bargaining and ignore
the other types of bargaining considered in this study.
Barros and Martinez-Giralt [5] analyse a bargaining pro-
cess in which the purchaser can choose whether to nego-
tiate with each provider separately or jointly, or announce a
contract that any provider is free to sign (the ‘‘any willing
provider’’ clause). They show that if the total surplus is
high, the purchaser prefers the system of ‘‘any willing
provider’’, but if it is low she prefers either joint or separate
negotiations. Again, the focus is on price bargaining. Gal-
Or [16] shows that purchasers (private insurers) might be
willing to sign exclusive contracts with a subset of pro-
viders in order to secure more favourable terms during
bargaining. Gal-Or [17] studies whether vertical mergers
between hospitals and physician practices might enhance
their bargaining power with the insurers (see also [18]).
Barros and Martinez-Giralt [4] explore the implications of
the coexistence of a public and a private sector in the
provision of health services. They argue that the public
sector might choose to hold idle capacity in order to extract
more beneficial conditions when bargaining with the pri-
vate sector for the provision of services. There are other
applications of bargaining in the health economics litera-
ture. Clark [10] examines how to divide a budget between
two patients with different health conditions and capacity
to benefit. Pecorino [31] models the effects of drug
reimports from Canada on the profitability of US domestic
pharmaceutical companies.2 With the exception of the
model by Ellis and McGuire [13], most of the existing
studies focus on price bargaining. Our main departure and
contribution to the literature is to compare different types
of bargaining models. The solution under price bargaining
is qualitatively analogous to those obtained in the cited
papers. The added value of our analysis consists in con-
sidering within the same set-up other forms of bargaining
(activity and efficient) in addition to price bargaining, to
compare them and to link the different regimes to different
institutional arrangements.
Some of the bargaining models presented below can be
interpreted as reduced forms of more complex institutional
bargaining arrangements between (public or private) pur-
chasing entities and associations (or organisations) of pri-
vate providers. A more detailed analysis of such
arrangements would quickly become intractable within the
current set up and are therefore outside the scope of this
study.
The study is organised as follows. ‘‘The model’’ presents
the model. ‘‘Regime comparison’’ provides a comparison
of the different scenarios. ‘‘Adding quality and effort’’
extends the model by adding quality and cost-containment
effort. ‘‘Extension’’ further extends the basic model by
endogenising the bargaining power of the purchaser and
the provider. ‘‘Conclusions’’ offers concluding remarks and
policy implications.
The model
We model the bargaining process between a purchaser of
health services, such as a health authority, and a provider (a
hospital). Define y as the number of patients treated and
p as the price the provider receives for each patient treated.
The provider’s utility U is given by its surplus U(p, y) =
py - C(y), where C(y) is the cost function of the provider,
which satisfies Cy [ 0, Cyy [ 0 (increasing marginal cost).
The purchaser’s utility (or health authority utility) is
given by the difference between the benefit for the patients
B(y) and the transfer to the provider: V(p, y) = B(y) - py.
The benefit function satisfies By [ 0 and Byy B 0.
A more general objective function for the purchaser is
B yð Þ � ð1þ kÞpyþ dU, where k is the opportunity cost of
public funds and d is the weight attached to the utility of
the provider. The main results of the analysis with this
more general specification would be qualitatively similar as
long as either k[ 0 or d\ 1. This is because a positive
1 Dor and Watson [12] evaluate how different payment mechanisms
affect the incentives in the relationship between hospitals and
physicians.
2 See also Wright [35] for a model of price regulation in the
pharmaceutical sector where the regulator and the pharmaceutical
company bargain over a subsidy.
Bargaining and the provision of health services 393
123
opportunity cost of public funds k simply implies a higher
marginal cost for the purchaser. The weight assigned to the
utility of the purchaser needs to be strictly less than one
(when k = 0), otherwise paying a higher price to the
hospital leaves the purchaser’s utility unchanged: the loss
from a higher price paid is exactly offset by the higher
revenues and utility of the provider. If d\ 1 higher
transfers to the provider reduce the utility of the purchaser,
which generates a tension between the purchaser and the
provider. For expositional simplicity, we focus on the
special case where k = d = 0.
We analyse three plausible scenarios. (1) Activity bar-
gaining: the purchaser sets the price (stage 1), and activity
is bargained between the purchaser and the provider (stage
2). (2) Price bargaining: the price is bargained between the
purchaser and the provider (stage 1), but activity is chosen
by the provider (stage 2). (3) Efficient bargaining: price and
activity are bargained simultaneously between the pur-
chaser and the provider.
Note that under scenarios (1) and (2) prices are deter-
mined before activity. This assumption is in line with the
institutional setting of several countries (see ‘‘Introduc-
tion’’). Prices are determined or agreed before the activity
takes place, i.e. before the hospital begins to treat the
patients. For example, prices are determined at the begin-
ning of the financial year, while activity (i.e. the number of
patients treated) is determined during the financial year (i.e.
after the resources allocation mechanism has been deter-
mined). In this respect, prices is a longer term decision
compared to activity.
Define c, with 0 B c B 1, as the bargaining power of the
purchaser, (1 - c) as the bargaining power of the provider,
V and U as the outside options for the purchaser and the
provider respectively, and eV ¼ V � V and eU ¼ U � U.
For notational simplicity let Vi = V(pi, yi), Ui = U(pi, yi),
where i = a, p, e denotes respectively activity, price and
efficient bargaining. In all the sections below we use Nash
bargaining to solve for optimal conditions [19, 27–29].3
Activity bargaining
In the first scenario, we assume that first the purchaser
chooses the price (stage 1), then the purchaser and the
provider bargain on activity (stage 2).4 We solve by
backward induction. For a given price p, the bargained
activity can be determined by solving:
maxy
BðyÞ � py� V� �c
py� CðyÞ � U� �1�c ð1Þ
The first order condition (FOC) is:
ya :ceVðBy � pÞ ¼ 1� c
eUðCy � pÞ ð2Þ
(See section The model in the Appendix for proof). To
interpret the optimal condition on the bargained activity it
is useful to characterise the solution on the basis of the
price level. We distinguish three possible cases. The first
(special) case is such that the price is bp ¼ ByðyÞ ¼ CyðyÞ,i.e. the price corresponds to the level where the marginal
benefit crosses the marginal cost. In such a case, the opti-
mal activity desired by the purchaser ðbp ¼ ByðyÞÞ is equal
to the activity desired by the provider ðbp ¼ CyðyÞÞ. The
equilibrium level of activity is such that By(ya) = Cy(ya).
The second case arises when p\bp which we refer to as
the ‘‘low’’ price. In this case we have that By(ya) [ p and
Cy(ya) [ p, i.e. the desired activity for the purchaser is
higher than the desired activity for the provider. The bar-
gained activity lies somewhere between the desired activity
of the two parties. The LHS of Eq. 2 is the net marginal
benefit of activity for the purchaser, weighted by her utility
and her bargaining power. The RHS is the net marginal
cost for the provider, also weighted by his utility and his
bargaining power.
The third case arises when p [ bp which we refer to as
the ‘‘high’’ price. In this case we have that p [ By(ya)
and p [ Cy(ya), i.e. the desired activity for the purchaser
is lower than the desired activity for the provider.
The FOC can be rewritten as c
eVp� By
� �
¼ 1�c
eUp� Cy
� �
.
Again, the bargained activity lies between the desired
activity of the two parties. We impose an upper bound
on the price: p [ p ¼ Byð0Þ: If p [ p ¼ Byð0Þ, then the
price is so high that the desired activity for the purchaser
is zero. Therefore, the equilibrium activity is character-
ised for any level of price between zero and an upper
bound p.
Figure 1 illustrates different bargained activity levels
[ya(p)] for three different values of the bargaining power of
the purchaser, equal to 0.3, 0.5 and 0.7, respectively. In
equilibrium it is always the case that eU � 0 and eV � 0, so
that the equilibrium lies in the area between the average
and marginal benefit, and the area between the average and
marginal cost.
Finally if p = By(ya) = Cy(ya) (i.e. where the marginal
benefit curve crosses the marginal cost curve), there is no
disagreement between purchaser and provider, so that ya is
such that By = Cy.
3 The Nash bargaining solution has been used extensively in labour
economics to examine negotiations between trade unions and firms
with respect to wages and employment. See, for example, Oswald
[30] for a survey of the literature, and Manning [22], McDonald and
Solow [23], Sampson [33] and Bulkley and Myles [7].4 A different interpretation is that the Department of Health fixes the
price, then the Health Authority and provider bargain on activity. The
implicit assumption is that the Department of Health and the Health
Authority share the same objective function.
394 L. Siciliani, A. Stanciole
123
By differentiating Eq. 2 with respect to c we obtain
oya
oc ¼ðBy�pÞeU�ðp�CyÞeV
eV eU ð�CÞ. If the price is low, a higher bar-
gaining power of the purchaser increases activity ðoya
oc [ 0Þ.If the price is high it reduces activity ðoya
oc \0Þ.The effect of a change of price on activity is:
oya
op¼ 1
�Cð1� cÞCy � C=y
eU2� c
B=y� By
eV 2
� �
ð3Þ
which in general is indeterminate. According to our
assumptions, it is always the case that Cy [ C/y and
B/y [ By, since the marginal cost is higher than the average
cost, and the average benefit is higher than the marginal
benefit. For low levels of p the provider utility eU is low (and
the purchaser utility eV is high) so that oya
op [ 0. Similarly, for
high levels of p the purchaser utility eV is low (and the
provider utility eU is high) so that oya
op \0 for low p. This
result is consistent with the example shown in Fig. 1.
The above analysis holds for a given price. The pur-
chaser chooses the price to maximise:
maxp
BðyaðpÞÞ � pyaðpÞ ð4Þ
The FOC is:
pa : Byyp ¼ yþ pyp ð5Þ
The optimal price is determined such that the marginal
benefit of higher activity equals the marginal cost. The
SOC is: Byyyp2 ? Byypp - 2yp - pypp. Dividing both terms
of Eq. 5 by yp, straightforward manipulations lead to
pa : By ¼ p 1þ 1
�yp
� �
where �yp ¼ ypp=y is the elasticity of activity with respect to
price. The optimal price is such that the marginal benefit
from activity is equal to the price, weighted by the inverse
of the elasticity of activity with respect to price: a higher
elasticity implies a lower marginal cost from an increase in
price, as intuitive.
Price bargaining
In the second scenario, we assume that first the purchaser and
the provider bargain on price (stage 1), then activity is chosen
unilaterally by the provider (stage 2).5 By backward induction,
for a given price, the hospital chooses the level of activity
which maximises U = py - C(y), leading to the FOC:
yp : p ¼ Cy ð6Þ
with oyp
op ¼ 1Cyy
[ 0 and o2yp
op2 ¼ 0 (the SOC is -Cyy \ 0). The
bargained price can be determined by solving:
maxp
BðypðpÞÞ � pypðpÞ � V� �c
pypðpÞ � CðypðpÞÞ � U� �1�c
ð7Þ
Thanks to the envelope theorem, Up = yp(p). The FOC for
the bargained price is:
pp :ceV
Byyp þð1� cÞeU
y ¼ cyþ pyp
eVð8Þ
(See section The model in the Appendix for proof). The
LHS of Eq. 8 is the benefit from a marginal increase in
price, and includes the marginal benefit for the purchaser
from a higher activity (weighted by her bargaining power,
her utility and the responsiveness of supply), and the
marginal benefit for the provider from a higher surplus
(also weighted by his bargaining power and utility). The
RHS is the cost for the purchaser from a marginal increase
in price and an overall higher transfer (also weighted).
If the purchaser holds all the bargaining power (c = 1),
the optimal price is such that: Byyp = y ? pyp. If the
provider holds all the bargaining power (c = 0), the opti-
mal price is the highest possible compatible with the pur-
chaser having a non-negative utility. The bargained price is
an intermediate level between these two extremes.
Efficient bargaining
In the third scenario, purchaser and provider bargain simul-
taneously on activity and price. This setting is called efficient
bargaining, because it reduces the potential for unexplored
opportunities from mutual gain.6 The bargaining problem is:
=0.3 =0.5 =0.7
Cy
By
yyB )(
or V=0
yyC )(
or U=0
y - Activity
High
price
Low
price
)( pya
Fig. 1 Activity bargaining
5 This setup is analogous to the model of bargaining between a firm
and a union over wage and employment [22, 23], where the firm sets
the employment, but the wage is bargained with the union.6 The outcome achieved in price bargaining is not efficient. As
remarked by Aronsson et al. [1], ‘‘there are unexplored profits and/or
utility gains from bargaining’’.
Bargaining and the provision of health services 395
123
maxp;y
BðyÞ � py� V� �c
py� CðyÞ � U� �1�c ð9Þ
After obtaining the FOCs and re-arranging, we obtain:
ye : By ¼ Cy ð10Þ
pe ¼ ð1� cÞBðyeÞ � V
yeþ c
CðyeÞ þ U
yeð11Þ
(See section The model in the Appendix for proof). The
negotiated level of activity maximises the sum of the
surplus for the purchaser and for the provider
U ? V = B(y) - C(y). In this respect the level of
activity is efficient. The optimal price is a weighted
average of the average cost of the provider and the average
benefit for the patients.7 If the purchaser holds all the
bargaining power (c = 1), the price is equal to the average
cost: the purchaser extracts all the surplus from the
provider. If the provider holds all the bargaining power
(c = 0), the price is equal to the average benefit: the
provider extracts all the surplus from the purchaser.
Regime comparison
Constant marginal benefit
To gain some insights into how the different scenarios
relate to each other, we consider the following functional
forms: (a) the benefit function is linear in activity:
B(y) = ay; (b) the cost function is quadratic: CðyÞ ¼ c2y2
with Cy = cy; (c) the outside options are normalised to
zero ðV ¼ U ¼ 0Þ.The equilibrium for the three scenarios is reported in
Table 1 (See section Constant marginal benefit in the
Appendix for proof).
The following proposition compares prices, activity and
utility under different regimes.
Proposition 1 (a) pe = pp C pa; (b) ye C {yp;ya},
yp C ya if c B 0.59; (c) Va C Ve C Vp; (d) Up C Ue C Ua
(e) Se C {Sp, Sa}; Sp [ Sa if c B 0.59.
(See section Constant marginal benefit in the Appendix
for proof). The price in efficient bargaining is equal to the
price in price bargaining, which is higher than or equal to
the price in activity bargaining. Compared to activity bar-
gaining, under both price and efficient bargaining, the
purchaser cannot set the price unilaterally but will have to
negotiate it with the provider. Since, in general, higher
price reduces the utility of the purchaser, the purchaser will
set a lower price when this can be decided unilaterally as
opposed to when it has to be negotiated (in which case the
provider will use some of the bargaining power to get a
better deal).
The activity in efficient bargaining is the highest. The
activity in price bargaining is higher than in activitybar-
gaining when the bargaining power of the purchaser is
below 0.59. Under efficient bargaining the activity is
chosen such that the marginal benefit is equal to the mar-
ginal cost, regardless of the bargained price. Under price
bargaining the activity is chosen unilaterally by the pro-
vider. Since the bargained price is strictly below the mar-
ginal (and average) benefit, and the activity is chosen such
that the price is equal to the marginal cost, it follows that
activity will be below the point where marginal benefit and
cost are equal. The result follows. Under activity bargain-
ing, the price chosen by the purchaser is set at relatively
low levels to keep payments to the provider low, which in
turn implies that the activity that the purchaser can nego-
tiate in return is lower compared to the efficient one (where
marginal benefit crosses the marginal cost).
The purchaser weakly prefers activity bargaining to
efficient bargaining, and efficient bargaining to price bar-
gaining. Since prices are lowest under activity bargaining,
the purchaser is better off under this scenario despite the
activity being lower compared to efficient bargaining.
Under price bargaining, activity is lower (which reduces
purchaser’s utility) compared to efficient bargaining while
prices are the same. Therefore, in this case it is the lower
activity that drives the lower purchaser’s payoff under
price as opposed to efficient bargaining. The results and
intuition are reversed from the provider’s perspective: the
provider weakly prefers price bargaining to efficient bar-
gaining, and prefers efficient bargaining to activity
bargaining.
Total surplus S, defined as the sum of provider’s and
purchaser’s utility (U ? V), is highest under efficient bar-
gaining. This is not surprising as, by definition, efficient
Table 1 Equilibrium with constant marginal benefit
Activity bargaining Price bargaining Efficient
bargaining
pa ¼ a2 pp ¼ að2�cÞ
2pe ¼ að2�cÞ
2
ya ¼ acð2�cÞ yp ¼ að2�cÞ
2cye ¼ a
c
Va ¼ a2
2cð2�cÞ Vp ¼ ca2ð2�cÞ4c
Ve ¼ ca2
2c
Ua ¼ a2ð1�cÞ2cð2�cÞ2 Up ¼ a2ð2�cÞ2
8cUe ¼ a2ð1�cÞ
2c
Sa ¼ a2ð3�2cÞ2cð2�cÞ2 Sp ¼ ð4�c2Þa2
8cSe ¼ a2
2c
7 This result is in line with the model of employment-wage
bargaining analysed by Manning [22] in the context of firm-union
negotiations. The level of employment does not depend on the payoffs
of firm and union. Consequently, they ‘‘can agree on this level and
then bargain about the distribution of the rents’’ ([22], p. 131).
396 L. Siciliani, A. Stanciole
123
bargaining is the procedure that maximises total surplus
(purchaser’s plus provider’s surplus). More interestingly,
both activity and price bargaining are inefficient, in the
sense that they do not maximise total surplus. Proposition 1
shows that the comparison between activity and price
bargaining is in general indeterminate: however, if the
bargaining power is below 0.59 then the surplus is higher
under price bargaining. The intuition for the result is the
following. Total surplus is maximised at ye = a/c where
the marginal benefit crosses the marginal cost. Activity is
always too low under activity and price bargaining because
ye C {yp;ya} so that the marginal benefit is strictly above
the marginal cost. Whether the surplus is highest under
activity or price bargaining depends on whether activity is
highest in either of the two regimes. But, as already dis-
cussed, activity is highest under price bargaining compared
to activity bargaining only for sufficiently high bargaining
power. The result follows.
One implication of our results is that if the provider
could choose between different bargaining regimes, the
provider would choose price bargaining, while the pur-
chaser would choose activity bargaining. Note that this is
in contrast to the result that the total surplus (the sum of the
surplus of provider and the purchaser) is highest under
efficient bargaining. Therefore, both the provider and the
purchaser would be willing to forego some of the total
surplus in favour of a more inefficient bargaining proce-
dure, which, however, maximises their own surplus. This
result may not arise if side payments between the parties
were costless and credible to make, in which case total
surplus would be maximised as under efficient bargaining,
and the surplus for provider and purchaser may be higher.
The results may help to explain some of the observed
institutional settings. In England, for example, the govern-
ment has moved from a system of ‘‘cost and volume’’ or
‘‘sophisticated’’ contracts’’ (described in the Introduction),
which is equivalent to efficient bargaining to a system of
‘‘payment by results’’, which is equivalent to activity bar-
gaining. As shown in proposition 1, although this move
increases the (public) purchaser’s payoff, it reduces the
provider’s one and total surplus. This may be explained by
the strong monopsony power of the government in England
(being the only buyer of public services from public hospi-
tals). The government has recently discussed the possibility
of moving to price bargaining where the prices are negotiated
between individual hospitals and local purchasers on the
ground that this may reflect more accurately the costs of the
hospital. Ultimately, price bargaining was not adopted in part
because of the fear of (local) purchasers paying too high
prices for care. Our model suggests that from the government
perspective this was the most rationale choice, since activity
bargaining under ‘‘payment by results’’ leads to a higher
payoff than under price bargaining.
Many European countries make use of DRG-type of
payments to remunerate hospitals (i.e. the equivalent of
payment by results in England), which in our framework
coincides with activity bargaining. This has become the
dominant payment system. Our analysis suggests that such
form of bargaining is, however, inefficient since it does not
maximise total surplus (though it does maximises pur-
chaser’s one) and generates welfare losses. Table 1 shows
that the welfare loss from having activity bargaining as
opposed to efficient bargaining is equal to: Se � Sa ¼a2
2cð1�cÞ2
ð2�cÞ2.8 A move from activity to efficient bargaining is not
interesting from the purchaser perspective. For the pur-
chaser to gain from a move from activity to efficient bar-
gaining would require hospitals to make side payments
(say a positive lump-sum transfer) from the hospitals to the
government. This is unlikely to happen as it is the pur-
chaser who ‘‘pays’’ for services and not the other way
around. The difficulty then of moving from activity to
efficient bargaining may therefore lie in the credibility of
making payments that go from the provider to the
purchaser.
To summarise, the purchaser is better off under activity
bargaining and the provider is better off in price bargain-
ing. Activity and surplus is highest in efficient bargaining
and prices are highest in efficient or price bargaining.
Figure 2 below displays the solution under different
regimes. An arrow indicates increasing bargaining power
of the purchaser. In efficient bargaining, a higher bargain-
ing power of the purchaser reduces prices but has no effect
on the level of activity. In activity bargaining, higher bar-
gaining power of the purchaser induces higher activity, but
has no effect on prices. In price bargaining, higher bar-
gaining power of the purchaser reduces both prices and
activity.
Interestingly, the solution in price bargaining, where the
purchaser holds all the bargaining power, coincides with
the solution in activity bargaining, where the provider has
all the bargaining power (point A). The solutions in price
and efficient bargaining coincide when the provider holds
all the bargaining power (point B). The solutions in activity
and efficient bargaining coincide when the purchaser holds
all the bargaining power (point C). Finally, the activity in
price bargaining is higher than in activity bargaining only
for low bargaining power of the purchaser.
Figure 2 also compares the solution when both parties
have the same bargaining power (c = 0.5). Prices are
higher in efficient and price bargaining (points Ec=0.5 and
8 Similarly, the welfare (total surplus) loss from having price
bargaining as opposed to efficient bargaining is equal to
Se � Sp ¼ a2
8cc2.
Bargaining and the provision of health services 397
123
Pc=0.5 respectively). Activity is highest in efficient bar-
gaining and lowest in activity bargaining (point Ac=0.5).
Decreasing marginal benefit
We extend the previous analysis, and assume a more
general specification of the benefit function: BðyÞ ¼ay� b
2y2, with decreasing marginal benefit, while we
maintain the other assumptions: CðyÞ ¼ c2y2, V ¼ U ¼ 0.
Table 2 reports the solution in price and efficient bargain-
ing. Proofs are in the Appendix (Decreasing marginal
benefit). The solution for activity bargaining is more
involved, and is derived separately in ‘‘Decreasing mar-
ginal benefit and activity bargaining’’.
The following proposition compares the two regimes.
Proposition 2 If c[ bbþc; then (a) pp [ pe, (b)
ye [ yp, (c) Up [ Ue, (d) Ve [ Vp.
If the bargaining power of the purchaser is sufficiently
high ðc[ bbþcÞ prices are higher in price bargaining,
activity is lower, the provider is better off and the pur-
chaser is worse off than under efficient bargaining. If the
bargaining power of the purchaser is sufficiently low
ðc\ bbþcÞ all the results are reversed. The threshold b
bþc
increases with b and decreases with c. Note that if b = 0
we are back to the results of proposition 1. Therefore, if the
purchaser has low bargaining power, efficient bargaining
yields a lower utility for the purchaser than in price bar-
gaining. This is a surprising result: we would expect the
purchaser to be better off when she can bargain with more
instruments, i.e. both prices and activity. But this holds true
only if her bargaining power is high. If her bargaining
power is low, having more instruments is counterproduc-
tive. The purchaser is better off when she cannot bargain
on activity.
Figure 3 below displays the solution under the two
regimes. The solutions in efficient and price bargaining are
depicted by line BC and AD respectively. An arrow indi-
cates increasing bargaining power of the purchaser. As
before, in efficient bargaining activity is constant, irre-
spective of the distribution of bargaining power, and the
price decreases as the bargaining power of the purchaser
increases. In price bargaining, both prices and activity
decrease as the bargaining power of the purchaser
increases.
It is useful to compare these results with those obtained
in the previous section by assuming constant marginal
benefit. When the bargaining power of the purchaser is
low, the activity in efficient bargaining is lower than in
price bargaining but with constant marginal benefit it is
always higher.
If the marginal benefit is constant (and equal to the
average benefit), the purchaser is always better off
regardless of its bargaining power: this arises because
activity is always higher under efficient bargaining than
under price bargaining, while the price is the same.
Activity under efficient bargaining is always determined
such that the marginal benefit is equal to the marginal cost.
yC
By
yBBy
)(=
E =0.5P =0.5y
yC )(
ACA =0.5
y - Activity
Fig. 2 Comparison of scenarios with constant marginal benefit
Table 2 Equilibrium with decreasing marginal benefit
Price bargaining Efficient bargaining
pp ¼ acð2�cÞbþ2c pe ¼ aðð1�cÞbþð2�cÞcÞ
2ðbþcÞ
yp ¼ að2�cÞbþ2c
ye ¼ abþc
Vp ¼ ca2ð2�cÞ2ðbþ2cÞ Ve ¼ ca2
2ðbþcÞ
Up ¼ a2cð2�cÞ2
2ðbþ2cÞ2Ue ¼ ð1�cÞa2
2ðbþcÞ
CyB
D
yB(y) or V=0
E =0.5 P =0.5
yC(y) or U=0
A=0.5
ByC
A
y - Activity
Fig. 3 Comparison of scenarios with decreasing marginal benefit
398 L. Siciliani, A. Stanciole
123
If the marginal benefit is strictly decreasing and the pur-
chaser has low bargaining power, activity under price
bargaining can be such that the marginal benefit is below
the marginal cost (so that activity is higher than under
efficient bargaining) but the average benefit is above the
price, so that the purchaser’s utility is positive. This cannot
arise if the marginal (and average) benefit is constant: if the
marginal benefit is below the cost, then the average benefit
would also be below the price, which in turn would imply a
negative utility for the purchaser: however, this can never
arise under Nash Bargaining as both parties always have
positive utilities in equilibrium. Therefore, the activity
under price bargaining will be always lower than under
efficient bargaining if the marginal benefit is constant.
Decreasing marginal benefit and activity bargaining
In this section we derive the solution under activity bar-
gaining. For a given price, the optimal bargained activity
is:
See section Decreasing marginal benefit and activity
bargaining in the Appendix for the proof. The optimal price
is given by the price which maximises V ¼ ayaðpÞ�b2yaðpÞ2 � pyaðpÞ. Given the complexity of the solution, it is
not possible to derive manageable expressions for price and
activity. To compare the solutions for the three scenarios
we resort to numerical simulations. Our strategy is to
specify a grid of values for all the parameters of the model
(a, b, c and c), and compute the solution numerically. We
fix a = 1, and specify a grid for b 2 f0; 0:5; 1; 1:5; . . .; 30g,c = {0, 0.5, 1, 1.5, … , 30} and c = {0, 0.1, … , 0.9, 1}.
For example, supposing that a = b = c = 1 and
c = 0.5, then yaðpÞ ¼ 34�
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
ðp� 1Þ2pþ 916
q
and
V ¼ ð1� pÞ 3
4�
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
ðp� 1Þ2pþ 9
16
r !
� 1
2
3
4�
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
ðp� 1Þ2pþ 9
16
r !2
the solution of which is pa = 0.29 and ya = 0.36. Table 3
reports the solution for a = b = c = 1 and c =
{0, 0.1, 0.25, 0.5, 0.75, 0.9, 1}. The tables for the other
values of b and c are omitted, but are available from the
authors.
Overall, the numerical simulations suggest that in
activity bargaining prices are lowest, the purchaser’s utility
is highest and the provider’s utility is lowest (note the
similarity with proposition 1). Activity is lower than in
efficient bargaining. It is lower than in price bargaining
when the bargaining power of the purchaser is below a
certain threshold, which is between 0.7 and 0.95 in our
simulations.
The solution in activity bargaining is displayed in Fig. 3
on the line AC, which was derived by plotting the
numerical solution 1,000 times. In contrast to the solution
with constant marginal benefit, in activity bargaining the
price is no longer fixed. As the bargaining power of the
purchaser increases, the price decreases and activity
increases.
As in the previous section, the solution in price bar-
gaining with c = 1 coincides with activity bargaining when
c = 0 (point A), and the solution in activity and efficient
bargaining coincide when c = 1 (point C). However, when
c = 0 (points B and D) efficient and price bargaining yield
different solutions. Finally, when both parties have the
same bargaining power, the solutions in efficient bargaining
and price bargaining coincide at the point where marginal
cost equals marginal benefit.
Finally, in price bargaining, an increase in the bar-
gaining power of the purchaser reduces prices and activity,
but in activity bargaining it reduces prices but increases
activity.
Adding quality and effort
In this section we extend the model by introducing quality
and cost containment effort, and we show that the results
using this more general specification are qualitatively
similar to the ones obtained above. We follow the approach
suggested by Ma [21] and Chalkley and Malcomson [9].
Define q as the quality generated by the provider and e as
the cost-containment effort. The cost function of the pro-
vider is Cðy; q; eÞ þ uðy; q; eÞ. C includes the monetary
cost, which increases with quality and activity but
decreases with effort: C(y, q, e), with Cy [ 0, Cq [ 0 and
yaðpÞ ¼2�c
2cða� pÞ þ bp1þc
2
� �
�ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
2�c2
cða� pÞ þ bp1þc2
� �2�2bcpða� pÞq
bcð12Þ
Bargaining and the provision of health services 399
123
Ce \ 0. u is the non-monetary cost, or disutility, which
increases with activity, quality and effort: uðy; q; eÞ, with
uy [ 0;uq [ 0 and ue [ 0.
We also assume that the demand for treatment depends
positively on quality so that y = y(q) with yq [ 0. This
assumption implies y = y(q), q = q(y), qy [ 0. Therefore
by contracting activity the purchaser can implicitly contract
the level of quality. The benefit function of the patients is
B = B(y, q) with By [ 0 and Bq [ 0. Since quality is a
positive function of activity, we can also write
B = B[y, q(y)] with oBoy ¼ oB
oy þ oBoq
oqoy [ 0. The provider’s
utility is given by the surplus: U ¼ py� Cðy; qðyÞ; eÞ�uðy; qðyÞ; eÞ. The purchaser’s utility is V = B[y, q(y)] -
py.
Activity bargaining
We assume that first the purchaser sets the price (stage 1);
second, purchaser and provider bargain on activity (stage
2); third, the provider chooses effort (stage 3). We solve by
backward induction. For a given price and activity (stage
3), the provider maximises the surplus U with respect to
effort so that:
Ueðe�Þ ¼ 0 : �Ceðy; qðyÞ; e�Þ ¼ ueðy; qðyÞ; e�Þ ð13Þ
The optimal effort for the provider e*(y) is such that the
marginal benefit of lower cost is equal to the marginal
disutility of effort. The indirect utility function of the
provider is Uðp; y; qðyÞ; e�ðyÞÞ ¼ py� Cðy; qðyÞ; e�ðyÞÞ�uðy; qðyÞ; e�ðyÞÞ.
For a given price (stage 2), the activity bargaining
problem between purchaser and provider is:
maxy
Vðp; y; qðyÞÞ � V� �c
Uðp; y; qðyÞ; e�ðyÞÞ � U� �1�c
ð14Þ
whose FOC is:
ya : cBy þ Bqqy � p
eV¼ ð1� cÞ
Cy þ uy þ ðCq þ uqÞqy � p
eU
ð15Þ
The volume of activity is such that the difference
between the marginal benefit and the price (weighted by
the relevant factors) equals the difference between the
marginal cost and the price (also weighted by the relevant
factors). The condition is analogous to Eq. 2. However, the
marginal benefit and marginal cost also include the
additional benefit and cost from higher quality. The
marginal cost includes both the monetary and non-
monetary cost.
In stage 1 the purchaser sets the price to maximise:
maxp
BðyaðpÞ; qðyaðpÞÞÞ � pyaðpÞ ð16Þ
The FOC is:
pa : Byyp þ Bqqyyp ¼ yþ pyp ð17Þ
The optimal price is such that the marginal benefit of
higher activity and quality induced by a higher price is
equal to the marginal cost.
Price bargaining
First the purchaser and the provider bargain on price (stage
1), and then the provider chooses the level of activity and
cost-containment effort (stage 2). We solve by backward
induction. For a given price (stage 2) the provider maxi-
mises the surplus U with respect to activity and effort, so
that:
Uyðy�; e�Þ ¼ 0 : p ¼ Cy þ uy þ ðCq þ uqÞqy ð18Þ
Ueðy�; e�Þ ¼ 0 : �Ce ¼ ue ð19Þ
Table 3 Numerical simulation
of equilibrium with decreasing
marginal benefit. Simulation
based on parameters
a = 1, b = 1, c = 1
c = 0 c = 0.1 c = 0.25 c = 0.5 c = 0.75 c = 0.9 c = 1
ya 0.33 0.33 0.34 0.36 0.40 0.44 0.50
ye 0.50 0.50 0.50 0.50 0.50 0.50 0.50
yp 0.67 0.63 0.58 0.50 0.42 0.37 0.33
pa 0.33 0.32 0.31 0.29 0.27 0.25 0.25
pe 0.75 0.70 0.63 0.50 0.38 0.30 0.25
pp 0.67 0.63 0.58 0.50 0.42 0.37 0.33
Va 0.17 0.17 0.18 0.19 0.21 0.23 0.25
Ve 0 0.03 0.06 0.13 0.19 0.23 0.25
Vp 0 0.03 0.07 0.13 0.16 0.17 0.17
Ua 0.06 0.05 0.05 0.04 0.03 0.02 0
Ue 0.25 0.23 0.19 0.13 0.06 0.03 0
Up 0.22 0.20 0.17 0.13 0.09 0.07 0.06
400 L. Siciliani, A. Stanciole
123
The provider chooses the level of activity, which
equates the price to the marginal monetary and non-
monetary cost. The marginal cost also takes into account
the indirect effect of activity caused by increased quality,
which is captured by the last term on the RHS. The optimal
effort is such that the marginal benefit of lower cost is
equal to the marginal disutility of effort. The indirect utility
function of the provider is U(p, y*(p), q(y*(p)), e*(p)).
Note that oy�
op ¼�Uee
UyyUee�U2ye[ 0, oe�
op ¼Uye
UyyUee�U2ye?0 and oU
op ¼y� (by the envelope theorem). The price bargaining
problem (stage 1) is given by:
maxp
Bðy�ðpÞ; qðy�ðpÞÞÞ�py�ðpÞ � V
c
py�ðpÞ � Cðy�ðpÞ; qðy�ðpÞÞ; e�ðpÞÞ�uðy�ðpÞ; qðy�ðpÞÞ; e�ðpÞÞ � U
1�c ð20Þ
The FOC is:
pp :ceVðBy þ BqqyÞyp þ
ð1� cÞeU
y ¼ ceVðyþ pypÞ ð21Þ
The optimal price is such that the weighted marginal
benefit for the purchaser of higher activity and quality, plus
the weighted marginal benefit for the provider in terms of
higher surplus, is equal to the weighted marginal cost for
the purchaser.
Efficient bargaining
First the purchaser and the provider bargain on price and
activity (stage 1), then the provider chooses the cost-con-
tainment effort (stage 2). By backward induction, for a
given activity and price (stage 2) the supplier maximises
the surplus U with respect to effort,
Ueðe�Þ ¼ 0 : �Ce ¼ ue ð22Þ
which provides e*(y). The bargaining problem is:
maxp;y
Bðy; qðyÞÞ � py� �V½ �c py� Cðy; qðyÞ; e�ðyÞÞ�uðy; qðyÞ; e�ðyÞÞ � U
1�c
ð23Þ
whose FOCs are:
ye : By þ Bqqy ¼ Cy þ uy þ qyðCq þ uqÞ ð24Þ
pe ¼ ð1� cÞB� V
yþ c
C þ uþ U
yð25Þ
The price equals the weighted sum of the average
benefit for the purchaser and the average cost of the
provider, which includes the non-monetary cost. The
optimal activity balances the purchaser’s marginal benefit
with the provider’s marginal cost.
Regime comparison
Suppose that the benefit and cost functions are separable in
activity, quality and effort, and that demand is linearly
increasing in quality: (a) Bðy; qÞ ¼ a1y� b1
2y2 þ a2q� b2
2q2;
(b) y = hq; Cðy; q; eÞ ¼ F þ c1
2y2 þ c2
2q2 � c3e, where F is a
fixed cost; (c) uðy; q; eÞ ¼ d1
2y2 þ d2
2q2 þ d3
2e2. ai, bi, di and h
are all positive parameters.
Define: bBðyÞ ¼ ða1 þ a2
h Þy� ðb1
2þ b2
2h2Þy2; bCðyÞ ¼ ðc1þd1
2
þc2þd2
2h2 Þy2; bV ðyÞ ¼ bBðyÞ � py� V ; bUðyÞ ¼ py� bCðyÞ �F� c3
2d3� U, where � c3
2d3¼ d3
2ðe�Þ2 � c3e� and e* is such
that �Ce ¼ ue.
Now, define: a ¼ ða1 þ a2
h Þ, b ¼ ðb1
2þ b2
2h2Þ, c ¼ ðc1þd1
2þ
c2þd2
2h2 Þ, and assume V ¼ 0 and U ¼ F þ c3
2d3.
Compare this formulation with ‘‘Decreasing marginal
benefit’’. It is straightforward to show that all results con-
tained in that section also hold for the more general for-
mulation developed in ‘‘Adding quality and effort’’.
Intuitively, since activity is an increasing function of
quality, by choosing or agreeing a certain level of activity,
the provider also determines the level of quality. Therefore,
adding quality adds complexity to the model but does not
alter the main incentives. The only difference is that the
marginal cost is now interpreted as the marginal cost of
activity and quality; similarly, the marginal benefit
includes the marginal benefit of activity and quality. For
what concerns effort, since the provider is residual claimant
in all the scenarios, effort is set such that marginal benefit
from lower cost is equal to the marginal disutility of effort,
regardless of the specific institutional setting. Therefore,
also adding this variable does not alter the main results of
the analysis.
Extension
In this section we assume that each party (i.e. the purchaser
and the provider) can exert costly investments that can
increase their bargaining power.9 We assume that the
bargaining power of the purchaser has the following linear
specification: c = c0 ? v - u, where v is the investment
by the purchaser to increase his bargaining power, and u is
the investment by the provider. Therefore, the bargaining
power of the provider is 1 - c = 1 - c0 - v ? u. Invest-
ment efforts are costly and are given by the function
K(v) for the purchaser and k(u) for the provider, respec-
tively. Investments are realised before the bargaining pro-
cess begins (simultaneously and non-cooperatively). We
9 We would like to thank an anonymous referee for suggesting this
extension.
Bargaining and the provision of health services 401
123
also assume that such investments are wasteful: their only
purpose is to increase the bargaining power but have no
effect on patients’ health. The purchaser’s and provider’s
utility under each bargaining procedure i (and excluding
the cost of investment efforts) is respectively equal to
V(pi(c), yi(c)) = [B(pi(c)) - pi(c)yi(c)] and U(pi(c), yi(c))
= pi(c)yi(c) - C(yi(c)) where i = a, p, e.
The optimal level of investment for the purchaser is
such that it maximises the following function:
maxv
ViðpiðcÞ; yiðcÞÞ � KðvÞ;
which gives the optimality condition:
oVi
oc¼ K 0ðv�Þ:
The marginal benefit from a higher investment, in terms of
larger bargaining power (and a higher payoff in the bar-
gaining stage) is equal to its marginal cost.
Similarly, the maximisation problem for the provider is:
maxu
UiðpiðcÞ; yiðcÞÞ � kðuÞ;
from which we obtain:
�oUi
oc¼ k0ðu�Þ:
A higher investment reduces c and increases the bargaining
power of the provider and his utility, which is traded-off
with its marginal cost.
We now ask how the incentives to invest in such costly
(but wasteful) investments to increase the bargaining
power varies across the three regimes. We focus on the
special case of proposition 1, which assumes constant
marginal benefit. It is straightforward to obtain that
oVe
ov ¼ a2
2c,oVp
ov ¼a2ð1�cÞ
2c and oVa
ov ¼ a2
2c1
ð2�cÞ2. It follows that the
marginal benefit from increasing the bargaining power is
highest under efficient bargaining oVe
ov [ foVa
ov ;oVp
ov g� �
, and
lower in the other two cases. Therefore, the incentive to
invest is highest when total surplus S is highest (and per-
haps counter-intuitively it is not when the utility of the
purchaser is highest).
For the provider we obtain: oUe
ou ¼ a2
2c,oUp
ou ¼ a2
2cð1�c2Þ and
oUa
ou ¼ a2
2cc
ð2�cÞ3. It follows again that the marginal benefit
from increasing the bargaining power is highest under
efficient bargaining oVe
ou [ foVa
ou ;oVp
ou g� �
, and lower in the
other two cases. Therefore, the incentive to invest is
highest when total surplus S is highest.
Note also that the marginal benefit from increasing the
bargaining power is the same for the purchaser and pro-
vider under efficient bargaining, it is higher for the provider
under price bargaining and it higher for the purchaser
under activity bargaining. Suppose that the K(v) = k(v), ie
the cost of the investment is the same for the purchaser and
the provider. It follows that under efficient bargaining
v* = u* and c = c0. Under price bargaining we have
u* [ v* and c\ c0. Under activity bargaining we have
v* [ u* and c[ c0.
A key insight from this extension is that wasteful
investments will be highest when the efficient bargaining
procedure is used. We have shown above that total surplus
is highest when the bargaining power is exogenous. As we
show below this is not necessarily the case when the bar-
gaining power is endogenous: since wasteful investments
are higher under efficient bargaining, welfare defined as the
surplus S minus the costly investments may be lower.
To make this point simply, we focus on efficient versus
price bargaining. We normalise a = c = 1. We also
assume that the cost function of the investments is qua-
dratic: K(v) = zv2/2 and k(u) = zu2/2, and that c0 = 0.5.
The optimal levels of investments under efficient bar-
gaining are: ve ¼ ue ¼ 12z, which gives a total cost of
investment KðveÞ þ kðueÞ ¼ 14z . Welfare, which is defined
as the surplus minus the costly investments, is Se�KðveÞ � kðueÞ ¼ 1
2ð1� 1
2zÞ.The optimal levels of investments under price bargain-
ing are obtained solving the simultaneous equation system
v ¼ 1�ð0:5þv�uÞ2z , u ¼ 1�0:5ð0:5þv�uÞ
2z , which gives: up ¼ 3zþ12zþ8z2
and vp ¼ 14zþ2ð1þ 3zþ1
4z2þzÞ. Welfare is equal to Sp � KðvpÞ�
kðupÞ ¼ 4�ð0:5þvp�upÞ28
� z2ðvpÞ2 � z
2ðupÞ2.
Figure 4 illustrates the comparison between the two
welfare functions for different values of the marginal cost
of the investment z. The welfare under efficient and price
bargaining is depicted with a red and a black line,
respectively. When investments are costly, i.e. z is high, we
recover the results obtained in the previous section. Wel-
fare is higher under efficient bargaining: graphically, the
1 2 3 4 5 6 7 8 9 10
-0.1
0.0
0.1
0.2
0.3
0.4
0.5
We
Wp
z
Fig. 4 Net surplus under efficient and price bargaining
402 L. Siciliani, A. Stanciole
123
red line is above the black one. When z is low, i.e.
investments are not very costly, then both parties will
engage in high levels of wasteful efforts that will increase
significantly wasteless expenditure (the red line lies below
the black one). Such expenditure is higher under efficient
bargaining, because as shown above the marginal benefit
from the investment is higher. For low levels of z, the latter
effect is so strong that overall welfare is higher under price
bargaining than under efficient bargaining. Finally, note
that when z is very low, wasteful expenditure is so high that
welfare is negative, and that efficient bargaining generates
a higher welfare for z [ 5.05.
Conclusions
Different countries have different institutional and bar-
gaining settings for purchasers and providers. They usually
follow one of three scenarios: the purchaser first sets the
price (stage 1), and activity is then bargained between
purchaser and provider (stage 2): activity bargaining; the
price is first bargained between purchaser and provider
(stage 1), but activity is then chosen unilaterally by the
provider (stage 2): price bargaining; and price and activity
are bargained simultaneously between purchaser and pro-
vider: efficient bargaining. This study has compared prices,
activity and the utility of provider and purchaser in each of
the three different institutional settings. We obtain three
main results:
First, if the bargaining power of the purchaser is higher
than a certain threshold and the marginal benefit of activity
is strictly decreasing, efficient bargaining leads to higher
activity and lower prices compared to price bargaining. As
a consequence, the purchaser’s utility is higher under effi-
cient bargaining than under price bargaining, while pro-
vider’s utility is lower. The results are reversed if the
bargaining power of the purchaser is below a certain
threshold: the activity is higher and the price are lower
under price bargaining rather than efficient bargaining.
Therefore, the purchaser’s utility is higher under price
bargaining than under efficient bargaining, while provider’s
utility is lower.
This result is surprising, as one would expect the pur-
chaser to be better off when she can bargain with both
instruments, price and activity. This intuition proves cor-
rect only when the bargaining power of the purchaser is
high. When it is low, the purchaser would be better off
contracting on prices only: having more instruments is not
useful, and actually is counter-productive. This is because
when the bargaining power of the purchaser is very low,
the provider will bargain a very high price, which under
price bargaining will be accompanied by a large volume of
activity. In contrast the level of activity under efficient
bargaining is always determined such that the marginal
benefit of quantity is equal to the marginal cost, regardless
of the price: therefore under efficient bargaining when the
purchaser is weaker, she will pay a higher price without
obtaining any extra activity.
Interestingly, the threshold level of bargaining power of
the purchaser over which the purchaser is better off,
depends critically on the shape of the marginal benefit
curve. The threshold is higher when the marginal benefit
function is steeper (i.e. the benefit function is more con-
cave) and when the marginal cost function is flatter (i.e. the
cost function is less convex).
Also, the threshold is strictly positive only when the
marginal benefit of activity is decreasing: if the marginal
benefit is constant (and equal to the average benefit), the
purchaser is always better off regardless of its bargaining
power (the threshold is zero in this case). Intuitively, this
arises because if the marginal benefit is constant, activity is
always higher under efficient bargaining than under price
bargaining, while the price is the same.
Activity under efficient bargaining is always determined
such that the marginal benefit is equal to the marginal cost.
If the marginal benefit is strictly decreasing and the pur-
chaser has low bargaining power, activity under price
bargaining can be such that the marginal benefit is below
the marginal cost but the average benefit is above the price,
so that the purchaser’s utility is positive. If the marginal
(and average) benefit is constant, having a level of activity
such that the marginal benefit is below the marginal cost
would imply that the average benefit is also below the
price. But this would imply a negative utility for the pur-
chaser, which can never arise as under Nash Bargaining
both parties always end up with positive utilities. Therefore
activity under price bargaining will be always lower than
under efficient bargaining if the marginal benefit is
constant.
Our second main result is that under activity bargaining,
price and provider’s utility are lowest and the purchaser’s
utility is highest. The level of activity in activity bargaining
is always lower than in efficient bargaining. It is also lower
than in price bargaining, but only if the bargaining power
of the purchaser is below a certain threshold (which,
according to our numerical simulations is above 50%). If
the bargaining power of the purchaser is high, then the
level of activity is higher under activity bargaining than
under price bargaining.
Even if activity is generally lower under activity bar-
gaining, the lower price more than compensates for the
reduction in the benefit for the patients from the lower
activity, so that the purchaser is overall better off. The
analysis therefore supports policies such as ‘‘payment by
results’’ in the UK, where prices are fixed by the purchaser
or the regulator.
Bargaining and the provision of health services 403
123
One perhaps less intuitive implication of our results is
that by shifting from efficient and price bargaining (as in
‘‘cost and volume’’ or ‘‘sophisticated’’ contracts) to activity
bargaining (as in ‘‘payment by results’’), the level of
activity is likely to decrease. This is in contrast to what is
normally thought, i.e. that ‘‘payment by results’’ will
encourage activity. However, our results are consistent
with recent empirical evidence [14], which finds that the
introduction of ‘‘payment by results’’ in 2003–2005 gen-
erally did not lead to any subsequent significant increase in
the volume of activity in England.
Our third result is that under price bargaining, higher
bargaining power of the purchaser reduces prices and
activity; in activity bargaining it reduces prices, but
increases activity; and in efficient bargaining it reduces
prices but has no effect on activity. Therefore, when the
bargaining power of the purchaser increases, price and
activity move in the same direction under price bargaining
but in opposite directions under activity bargaining.
The intuition for these results is the following. Under
price bargaining, the optimal activity is chosen by the
provider such that the price is equal to the marginal cost.
Therefore, whenever the price increases, as a result of a
stronger purchaser, activity follows. Under efficient bar-
gaining, the optimal activity is such that it maximises the
sum of the purchaser and provider utility. Since purchaser’s
utility is given by the benefit minus the transfer to the
provider, while provider’s utility is given by the transfer
minus the cost, this is equivalent to maximise the differ-
ence between benefit and cost. The optimal activity is
chosen such that the marginal benefit is equal to the mar-
ginal cost of activity, regardless of the bargaining power.
Therefore, a stronger purchaser will obtain a lower price
but not a lower activity. Under activity bargaining, a
stronger purchaser is able to agree with the provider a
higher volume of activity for a given price; if the marginal
benefit of activity is decreasing, the higher agreed activity
reduces the marginal benefit for the purchaser from fixing a
higher price, so that the price is lower and activity is higher
when the purchaser is stronger.
The above results are derived in ‘‘The model’’ and
‘‘Regime comparison’’ and focus on price and activity
only. In Adding quality and effort we extended the analysis
by adding quality and cost-containment effort as choice
variables of the provider. This makes activity bargaining a
three-stage model, and efficient and price bargaining a two-
stage model. Cost-containment effort is always decided by
the provider in the last stage of the game as, realistically,
effort takes place after the negotiation stage, i.e. the
beginning of the financial year. We assume that demand
responds positively to quality. Therefore, the quality
decisions always happen when decisions on activity take
place. This is because by committing or deciding on a
certain level of activity, indirectly the provider commits as
well to a certain level of quality.
We show that under this more general setting, the main
results of the analysis in terms of regime comparison still
hold. The only difference is that the marginal cost is now
interpreted as the marginal cost and disutility of activity
and quality; similarly, the marginal benefit includes the
marginal benefit of activity and quality. For what concerns
cost-containment effort, since the provider is residual
claimant in the three different settings, effort is always set
such that marginal benefit from lower cost is equal to the
marginal disutility of effort, regardless of the institutional
setting. Therefore, adding effort to the analysis does not
alter the main results.
In ‘‘Extension’’ we show that, although welfare is higher
under efficient bargaining for a given bargaining power,
this may not be the case when bargaining power is
endogenised and the marginal cost of wasteful effort is
sufficiently low. This arises because the returns from
wasteful investments are highest when the efficient bar-
gaining procedure is used, so that welfare net of the
wasteful investment may now be lower under efficient
bargaining compared to the other bargaining procedures.
In terms of implications for future work, there is a need
for empirical work that quantifies the bargaining power of
the purchaser and the provider in health care markets. This
might help governments to decide whether to encourage
purchasers to bargain on prices only, or on price and
activity simultaneously. Moreover, most of the empirical
work focuses on the effect of bargaining power on prices
[2]. This study provides clear predictions of the effect of
the bargaining power on activity as well as price. More
precisely, under price bargaining, a higher bargaining
power of the purchaser reduces activity; under activity
bargaining it increases activity; and under efficient bar-
gaining it has no effect on activity. Future empirical work
might test such predictions. We have also shown that a
switch from efficient to price bargaining does not neces-
sarily lead to an increase in activity. Further empirical
work might test whether policies such as ‘‘payment by
results’’ are likely to increase or decrease activity com-
pared to previous policies. On the theory side, more work is
needed which integrates bargaining models with political-
economy ones.
Appendix
The model
Proof of Eq. 2. Activity bargaining The result is obtained
by differentiating c log½BðyÞ � py� V � þ ð1� cÞ log½py�CðyÞ � U� with respect to y. The second order condition
404 L. Siciliani, A. Stanciole
123
(SOC) is C ¼ cByyV�ðBy�pÞ2
eV 2� ð1� cÞCyy
eUþðp�CyÞ2
eU 2\0, which
is always satisfied. h
Proof of Eq. 8. Price bargaining By taking the log
and differentiating with respect to p we obtain
cByyp�yðpÞ�pyp
eVþ ð1� cÞyðpÞþpyp�Cyyp
eU¼ 0. From the FOC of
the provider we know that p = Cy. By simplifying, we
obtain: cByyp�yðpÞ�pyp
eVþ ð1� cÞyðpÞ
eU¼ 0. The SOC is
�ceU 2ððBy�pÞyp�yÞ2þð1�cÞeV 2y2
eV 2eU 2
�cð2�Byy
CyyÞeU�ð1�cÞeVeV eU
yp. h
Proof of Eq. 11. Efficient bargaining Define
X ¼ BðyÞ � py� V� �c
py� CðyÞ � U� �1�c
Then: o log Xop ¼ �
cy
BðyÞ�py�Vþ ð1�cÞy
py�CðyÞ�U¼ 0 and o log X
oy ¼cðBy�pÞ
BðyÞ�py�Vþ ð1�cÞðp�CyÞ
py�CðyÞ�U¼ 0. From the first equation we
obtain p ¼ c½CðyÞþU�þð1�cÞ½BðyÞ�V �y , which, substituted into
the second one, yields: By = Cy. The SOCs are:
o2 log Xop2 ¼ �y2ð c
~V2 þ 1�c~U2 Þ\0, o2 log X
oy2 ¼ cByy~V�ðBy�pÞ2
~V2 � ð1� cÞCyy
~Uþðp�CyÞ2~U2 \0, and o2 log X
op2
o2 log Xoy2 [ ðo
2 log Xopoy Þ
2. o2 log X
opoy ¼ �c~V
þ1�c~Uþ yðBy � pÞð c
~V2 þ 1�c~U2 Þ ¼ ð1�cÞBþcC�py
~V ~Uþ yðBy � pÞð c
~V2
þ1�c~U2 Þ ¼ yðBy � pÞð c
~V2 þ 1�c~U2 Þ, where the last simplification
follows from the FOC for price. o2 log Xop2
o2 log Xoy2 [ ðo
2 log Xopoy Þ
2 ¼
�y2ð c~V2 þ 1�c
~U2 Þ½cByy
~V~V2 � ð1� cÞCyy
~U~U2 � ðBy � pÞ2ð c
~V2 þ 1�c~U2 Þ��
y2ðBy � pÞ2ð c~V2 þ 1�c
~U2 Þ2¼ �cByy~V
~V2 þ ð1� cÞCyy~U ~U2 [ 0. All
three SOCs are always satisfied, since Byy B 0. h
Constant marginal benefit
Activity bargaining. pa ¼ a2, ya ¼ a
cð2�cÞ, Va ¼ a2
2cð2�cÞ,
Ua ¼ a2ð1�cÞ2cð2�cÞ2.
Proof The rule determining activity is, for a given price:
c a�pða�pÞyþ ð1� cÞ p�cy
ðp�c2yÞy ¼ 0, from which y ¼ 2p
cð2�cÞ. The
FOC for price is: 2acð2�cÞ �
4pcð2�cÞ ¼ 0, from which: pa ¼ a
2
(the SOC is � 4pcð2�cÞ\0). The bargained activity is there-
fore: ya ¼ acð2�cÞ. The utility of the purchaser and the pro-
vider are: Va ¼ ða� pÞy ¼ a2
2cð2�cÞ and Ua ¼ ðp� c2yÞy
¼ a2ð1�cÞ2cð2�cÞ2. h
Price bargaining. pp ¼ að2�cÞ2
, yp ¼ að2�cÞ2c , Vp ¼ ca2ð2�cÞ
4c ,
Up ¼ a2ð2�cÞ28c .
Proof Since y ¼ pc with yp ¼ 1
c, the FOC for the bargained
price is: cða�pÞ1c�pc
apc�
p2
c
þ ð1� cÞpc
p2
c �p2
2c
¼ 0, which gives: pp ¼að2�cÞ
2(the SOC is � 1
ða�pÞ2p2ðða� pÞ2 þ p2Þ � 2
p2ð1� cÞ\0).
Hence yp ¼ að2�cÞ2c , Vp ¼ ða� pÞy ¼ ca2ð2�cÞ
4c and Up ¼ ðp�c2yÞy ¼ a2ð2�cÞ2
8c . h
Efficient bargaining. pe ¼ að2�cÞ2
, ye ¼ ac, Ve ¼ ca2
2c , Ue ¼a2ð1�cÞ
2c .
Proof The FOC with respect to price implies:
p ¼ ð1� cÞaþ cc2y. The FOC with respect to activity
implies: ye ¼ ac. Therefore pe ¼ að2�cÞ
2and Ve ¼ ða� pÞy ¼
ca2
2c and Ue ¼ ðp� c2yÞy ¼ ð1� cÞa2
2c. h
Proof of Proposition 1 (a) pp ¼ að2�cÞ2� a
2¼ pa if c B 1.
(b) ya ¼ acð2�cÞ � ye ¼ a
c if acð2�cÞ � a
c or c B 1; yp ¼að2�cÞ
2c � ye ¼ ac if c C 0; yp ¼ að2�cÞ
2c � ya ¼ acð2�cÞ if (2 -
c)2 C 2 or c B 0.59. (c) Va ¼ a2
2cð2�cÞ �Ve ¼ ca2
2c if 2c -
c2 - 1 B 0 or -(c - 1)2 B 0; Ve ¼ ca2
2c �Vp ¼ ca2ð2�cÞ4c if c
C 0. (d) Up ¼ a2ð2�cÞ28c �Ue ¼ a2
2cð1� cÞ ifð2�cÞ2
4�ð1� cÞ
or 4 ? c2 - 4c C 4 - 4c, or if c2 [ 0; Ue ¼ a2
2cð1�
cÞ�Ua ¼ a2
2c1�cð2�cÞ2 if (2 - c)2 C 1, which is always the
case, since 0 B c B 1. h
Decreasing marginal benefit
Price bargaining. pp ¼ acð2�cÞbþ2c , yp ¼ að2�cÞ
bþ2c , Vp ¼ ca2ð2�cÞ2ðbþ2cÞ ,
Up ¼ a2cð2�cÞ2
2ðbþ2cÞ2 .
Proof Since y ¼ pc with yp ¼ 1
c, the FOC for the bargained
price is: cða�bpc�pÞ1c�
pc
ðapc�b
2p2
c2�p2
c Þþ ð1� cÞ
pc
p2
c �p2
2c
¼ 0, which simplifies
to cða�bpc�pÞ�p
ða�b2
pc�pÞ þ 2ð1� cÞ ¼ 0 or cða� bp
c � pÞ � cpþ 2
ð1� cÞða� b2cp� pÞ ¼ 0, giving: pp ¼ acð2�cÞ
bþ2c . Hence
yp ¼ að2�cÞbþ2c , Vp ¼ ða� b
2y� pÞy ¼ ca2ð2�cÞ
2ðbþ2cÞ and Up ¼
ðp� c2yÞy ¼ a2cð2�cÞ2
2ðbþ2cÞ2 . h
Efficient bargaining. pe ¼ aðð1�cÞbþð2�cÞcÞ2ðbþcÞ , ye ¼ a
bþc,
Ve ¼ ca2
2ðbþcÞ, Ue ¼ a2ð1�cÞ2ðbþcÞ .
Proof The FOC with respect to price implies:
pe ¼ ð1� cÞða� b2yÞ þ ccy
2. The FOC with respect to
activity implies: ye ¼ abþc. Therefore pe ¼ aðð1�cÞbþð2�cÞcÞ
2ðbþcÞ
Bargaining and the provision of health services 405
123
and Ve ¼ ða� b2y� pÞy ¼ ca2
2ðbþcÞ and Ue ¼ ðp� c2yÞy ¼
a2ð1�cÞ2ðbþcÞ . h
Proof of Proposition 2 (a) pp [ pe ifacð2�cÞ
bþ2c [aðð1�cÞbþð2�cÞcÞ
2ðbþcÞ or b(cc ? bc - b) [ 0 or c [ bbþc.
(b) ye [ yp if abþc [ að2�cÞ
bþ2c or b ? 2c - (2 - c) (b ? c) [ 0
or c [ bbþc. (c) Up [ Ue if
a2cð2�cÞ2
2ðbþ2cÞ2 [ ð1�cÞa2
2ðbþcÞ or
b2c ? bcc2 ? c2c2 - b2 [ 0 or c ¼ f�bc;
bbþcg. (d) Ve [ Vp
if ca2
2ðbþcÞ[ca2ð2�cÞ2ðbþ2cÞ or (b ? 2c) - (b ? c) (2 - c) [ 0 or
c[ bbþc. h
Decreasing marginal benefit and activity bargaining
Proof From FOC with respect to y we have c ða�byÞ�p
ay�b2y2�py
¼�ð1� cÞ p�cy
py�c2y2 or cða� by� pÞðp� c
2yÞ þ ð1� cÞðp� cyÞ
ða� b2y� pÞ ¼ 0. Upon expanding, we obtain
bc2
y2 � yðc2�c2ða� pÞ þ bp1þc
2Þ þ pða� pÞ ¼ 0, with solu-
tion y ¼ ðc2�c
2ða�pÞþbp1þc
2Þ�
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
ðc2�c2ða�pÞþbp1þc
2Þ2�4bc
2pða�pÞ
pbc . h
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