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Chapter 11Chapter 11
Incorporating Dynamics
Through the Use of
Distributed Lags
Section 11.1Section 11.1
Introduction
Arise in theory when economic stimuli produce their effect only after some lag in time.
Effects are not felt all at once but instead are distributed over a period of time.
Types:
Distributed Lag Models
Types:
(1) Free-form
(2) Geometric Lag
(3) Almon (Polynomial Distributed) Lag
(4) Partial Adjustment Hypothesis
3
- SR Effects
- LR Effects
Information from Distributed Lag Models
- Mean Lag
4
tmtm
1t1t0
t2t10t
ADVw...
ADVwADVw
INCOMEPRICESALES
ε+++++
β+β+β=
−
−
0wffecte SR →
Example
effect
m
0ii
m
0ii
LR
iwagl MEAN
wfectef LR
∑
∑
=
=
→
→
5
1. Psychological
2. Technical
3. Institutional
Distributed Lags Attributed to Four Factors
3. Institutional
4. Imperfect Knowledge or Uncertainty
Griliches (1967)
Dhrymes (1971)
6
Section 11.2Section 11.2
Approaches to Distributed
Lag Models
1. No assumptions as to the form of distribution of weights (free form)
2. Assume a distribution of weights: a general
form for the distribution of lag (geometric
Approaches
form for the distribution of lag (geometric
and Almon lags)
3. Nerlovian LagsExplicit dynamic model which implies a distributed lag only incidentally
8
(1) No assumption as to the form of the distributi on;weights associated with various lags are an empiric al issue .
....Xw...XwXwXwXwY
tmtm
3t32t21t1t00t
ε++++++++α=
−
−−−
Approaches to Estimating Distribution of a Lag
Incorporate all conceivable lags and estimate.
Problems
* Finite number of observations in most time serie s -reduces degrees of freedom
* Possible collinearity with X t, Xt-1, . . . , Xt-m.
9
Section 11.3Section 11.3
SAMPLE PROBLEM:
Free- Form Lag
Orange Juice Problem: Free-Form Distributed Lag****************************************************************************************DEMAND ANALYSIS FOR ORANGE JUICE USING SCANNER DATA FROM RETAIL FOOD STORES
RETAIL FOOD STORES IN EXCESS OF $2 MILLION ANNUALLY
ALLOJGALPC--PER CAPITA ORANGE JUICE CONSUMPTION IN GALLONS
RALLOJPRICE--REAL PRICE OF ORANGE JUICE, DOLLARS PER GALLON
RALLGFJPRICE--REAL PRICE OF GRAPEFRUIT JUICE, DOLLARS PER GALLONRPCDPI--REAL PER CAPITA DISPOSABLE PERSONAL INCOME, DOLLARS
SC0996--DUMMY VARIABLE, BEGINNING IN SEPTEMBER 1996 WALMART PART OF THE DATA COLLECTION
ROJFDOCADEXP--REAL ADVERTISING EXPENDITURES ON ORANGE JUICE BY THE FLORIDA DEPT OF CITRUS,THOUSAND DOLLARS***********************************************************************************11
/* Read in the RAW DATA */ /* STATEMENT*/
data Orange_Juice_FDOC_Data;input MONTH YEAR ALLOJGALPC RALLOJPRICERALLGFJPRICE RPCDPI SC0996 ROJFDOCADEXP;
* logarithmic transformation of variables; * logarithmic transformation of variables; lallojgalpc=log(allojgalpc); lrallojprice=log(rallojprice);
lrallgfjprice=log(rallgfjprice); lrpcdpi=log(rpcdpi); lrojfdocadexp=log(rojfdocadexp);
* creation of lags of lrojfdocadexp variable;lag1rfdocad=lag1(lrojfdocadexp);lag2rfdocad=lag2(lrojfdocadexp);lag3rfdocad=lag3(lrojfdocadexp);lag4rfdocad=lag4(lrojfdocadexp);
12
* seasonality through the use of monthly dummy variables;m1=0; m2=0; m3=0; m4=0; m5=0; m6=0; m7=0; m8=0; m9=0;
m10=0; m11=0; m12=0;if month=1 then m1=1;if month=2 then m2=1;if month=3 then m3=1;if month=4 then m4=1;if month=5 then m5=1;if month=6 then m6=1; if month=6 then m6=1; if month=7 then m7=1;if month=8 then m8=1;if month=9 then m9=1;if month=10 then m10=1;if month=11 then m11=1;if month=12 then m12=1;
datalines;13
options nodate;run;
***********************************************************************GLS procedure to run a free-form distributed lag **********************************************************************;
* correction for serial correlation;
14
* correction for serial correlation; Proc autoreg data = Orange_Juice_FDOC_Data;
model lallojgalpc = lrallojprice lrallgfjprice lrpcdpi
sc0996 lrojfdocadexp lag1rfdocad lag2rfdocad lag3rfdocad lag4rfdocad m1-m11 / nlag=2 method=ml;
run;
Graph of Per Capita Monthly Orange Juice
Consumption, January 1989 to September 2002
.28
.30
ALLOJGALPC
15
.20
.22
.24
.26
89 90 91 92 93 94 95 96 97 98 99 00 01 02
Graph of Real (Inflation-Adjusted) FDOC Advertising
Expenditures for Orange Juice Over the Period
January 1989 to September 2002
4,000
ROJFDOCADEXP
16
0
1,000
2,000
3,000
89 90 91 92 93 94 95 96 97 98 99 00 01 02
Free-Form Distributed Lag
Dependent Variable lallojgalpc
Ordinary Least Squares Estimates
SSE 0.10645428 DFE 140
17
SSE 0.10645428 DFE 140
MSE 0.0007604 Root MSE 0.02758
SBC -615.14479 AIC -679.85428
MAE 0.01899552 AICC -673.2068
MAPE 1.37380851 Regress R-Square 0.8537
Durbin-Watson 0.4622 Total R-Square 0.8537
continued...
Standard Approx
Variable DF Estimate Error t Value Pr > |t|
Intercept 1 0.8317 0.9011 0.92 0.3577
lrallojprice 1 -0.3887 0.0314 -12.38 <.0001
lrallgfjprice 1 0.3157 0.0517 6.10 <.0001
lrpcdpi 1 -0.2314 0.0954 -2.43 0.0166
SC0996 1 0.0460 0.009401 4.89 <.0001
lrojfdocadexp 1 -0.000542 0.002529 -0.21 0.8305
lag1rfdocad 1 0.002803 0.002759 1.02 0.3113
lag2rfdocad 1 0.002247 0.002816 0.80 0.4262
lag3rfdocad 1 0.003565 0.002764 1.29 0.1992 lag3rfdocad 1 0.003565 0.002764 1.29 0.1992
lag4rfdocad 1 0.002968 0.002559 1.16 0.2480
m1 1 0.0420 0.0114 3.70 0.0003
m2 1 -0.1087 0.0115 -9.47 <.0001
m3 1 -0.0247 0.0110 -2.24 0.0270
m4 1 -0.1034 0.0114 -9.05 <.0001
m5 1 -0.0956 0.0112 -8.58 <.0001
m6 1 -0.1465 0.0110 -13.37 <.0001
m7 1 -0.1234 0.0112 -10.97 <.0001
m8 1 -0.0966 0.0109 -8.85 <.0001
m9 1 -0.0974 0.0111 -8.81 <.0001
m10 1 -0.0501 0.0110 -4.56 <.0001
m11 1 -0.0678 0.0113 -5.97 <.0001 18 continued...
Maximum Likelihood Estimates
SSE 0.0339825 DFE 138
MSE 0.0002463 Root MSE 0.01569
SBC -786.23376 AIC -857.10606
MAE 0.01091217 AICC -849.04767
MAPE 0.79567375 Regress R-Square 0.9386
19
MAPE 0.79567375 Regress R-Square 0.9386
Durbin-Watson 1.8655 Total R-Square 0.9533
continued...
Standard Approx
Variable DF Estimate Error t Value Pr > |t|
Intercept 1 1.5658 1.6965 0.92 0.3577
lrallojprice 1 -0.8069 0.0741 -10.89 <.0001
lrallgfjprice 1 0.3817 0.1041 3.67 0.0003
lrpcdpi 1 -0.2655 0.1783 -1.49 0.1386
SC0996 1 0.0368 0.0156 2.36 0.0198
lrojfdocadexp 1 0.001138 0.001364 0.83 0.4054
lag1rfdocad 1 0.002392 0.001359 1.76 0.0807
lag2rfdocad 1 0.001550 0.001335 1.16 0.2478
lag3rfdocad 1 0.002980 0.001333 2.23 0.0270
lag4rfdocad 1 0.001504 0.001362 1.10 0.2712
m1 1 0.0428 0.005399 7.92 <.0001
m2 1 -0.1006 0.005653 -17.79 <.0001
Sum of coefficients associated with advertising and promotion corresponds to the long-run elasticity 0.009564. The mean lag Is equal to 2.14 months.
20
m2 1 -0.1006 0.005653 -17.79 <.0001
m3 1 -0.0156 0.006137 -2.54 0.0121
m4 1 -0.0896 0.006814 -13.14 <.0001
m5 1 -0.0833 0.006984 -11.92 <.0001
m6 1 -0.1344 0.006879 -19.54 <.0001
m7 1 -0.1110 0.006906 -16.07 <.0001
m8 1 -0.0884 0.006520 -13.56 <.0001
m9 1 -0.0918 0.006132 -14.96 <.0001
m10 1 -0.0479 0.005454 -8.79 <.0001
m11 1 -0.0641 0.004931 -13.00 <.0001
AR1 1 -0.6502 0.0813 -8.00 <.0001
AR2 1 -0.3174 0.0815 -3.89 0.0002
(2) Assume a distribution to the lag, with its associated parameters.
Example 1 Geometric Lag
Geometric Lag
Weights declining geometrically with time
.10,WW 0i
i <λ<λ=
21
Coefficients decline geometrically; that is, the closest lags carry the heaviest weight. Expression for any coefficient
k λλ <<==
Geometric Lags: Koyck Distributed Lags
General lag structure
Nonlinear Model
.......
.10 ...2,1,0
0100
0
tmtm
ttt
kk
XWXWXWY
kWW
ελλα
λλ
++++++=
<<==
−−
22
Useful to describe the lag structure of a distributed lag model: (1) in terms of its mean or average lag, and (2) in terms of the long-run response of the dependent variable to a permanent change in one of the explanatory variables.
The long-run response in the geometric lag model is:
∑
=
m
ssW
0
The long-run response measures the change in Y associated with a one-unit change in X which stays in effect for all time.
Mean lag refers to the average length of time for a (unit) change in the explanatory variable X to be transferred to the dependent variable.
ss
m
s
m
sss WWWsWmean λ0
0 0
/lag ==∑ ∑= =
23
Section 11.4Section 11.4
SAMPLE PROBLEM:
Geometric Lag
options nodate;run;***************************************************************************Conventional model with correction for serial correlation; proc model data = Orange_Juice_FDOC_Data;parms a0 a1 a2 a3 a4 a5 a6 a7 a8 a9 a10 a11 a12 a13 a14 a15 a16 a17 a18 a19 a20;
lallojgalpc = a0 + a1*lrallojprice + a2*lrallgfjprice + a3*lrpcdpi + lallojgalpc = a0 + a1*lrallojprice + a2*lrallgfjprice + a3*lrpcdpi +
a4*sc0996 + a5*lrojfdocadexp + a6*lag1rfdocad + a7*lag2rfdocad
+ a8*lag3rfdocad + a9*lag4rfdocad + a10*m1 + a11*m2 + a12*m3
+ a13*m4 + a14*m5 + a15*m6 + a16*m7 + a17*m8 + a18*m9 +
a19*m10 + a20*m11;
%ar(lallojgalpc,2);fit lallojgalpc / dw;
25 continued...
run; GLS procedure to run a geometric distributed lag
* correction for serial correlation; proc model data=Orange_Juice_FDOC_Data;parms a0 a1 a2 a3 a4 a5 a6 a10 a11 a12 a13 a14 a15 a16 a17 a18 a19 a20;
lallojgalpc = a0 + a1*lrallojprice + a2*lrallgfjprice + a3*lrpcdpi +
a4*sc0996 + a5*lrojfdocadexp + a5*a6*lag1rfdocad +
a5*a6*a6*lag2rfdocad + a5*a6*a6*a6*lag3rfdocad + a5*a6*a6*lag2rfdocad + a5*a6*a6*a6*lag3rfdocad +
a5*a6*a6*a6*a6*lag4rfdocad + a10*m1 + a11*m2 + a12*m3 +
a13*m4 + a14*m5 + a15*m6 + a16*m7 + a17*m8 + a18*m9 +
a19*m10 + a20*m11;%ar(lallojgalpc,2);fit lallojgalpc start=(a0=1.56 a1=-.8 a2=.4 a3=-.3 a4=.04 a5=.001138 a6=.5) / dw; run;
26
The MODEL Procedure
OLS Estimation Summary
Data Set Options
DATA= ORANGE_JUICE_FDOC_DATA
Minimization Summary
Parameters Estimated 23
Method Gauss
Iterations 8
Final Convergence Criteria Final Convergence Criteria
R 0.000305
PPC(a0) 0.000624
RPC(a0) 0.003645
Object 1.916E-6
Trace(S) 0.000247
Objective Value 0.000212
Observations Processed
Read 165
Solved 165
Used 161
Missing 4 27
Nonlinear OLS Summary of Residual Errors
DF DF
Equation Model Error SSE MSE
lallojgalpc 23 138 0.0341 0.000247
28
lallojgalpc 23 138 0.0341 0.000247
Adj Durbin
Root MSE R-Square R-Sq Watson
0.0157 0.9531 0.9456 2.1052
Nonlinear OLS Parameter Estimates
Approx Approx
Parameter Estimate Std Err t Value Pr > |t| Label
a0 1.556093 1.7677 0.88 0.3802
a1 -0.82047 0.0735 -11.17 <.0001
a2 0.390448 0.1038 3.76 0.0002
a3 -0.25617 0.1869 -1.37 0.1728
a4 0.03731 0.0157 2.37 0.0191
a5 0.001134 0.00135 0.84 0.4037
a6 0.002355 0.00135 1.74 0.0834
a7 0.001524 0.00133 1.15 0.2527
a8 0.002975 0.00132 2.25 0.0261
a9 0.001466 0.00135 1.08 0.2800
a10 0.043003 0.00538 7.99 <.0001
29
a10 0.043003 0.00538 7.99 <.0001
a11 -0.1003 0.00560 -17.91 <.0001
a12 -0.01538 0.00608 -2.53 0.0125
a13 -0.08925 0.00674 -13.24 <.0001
a14 -0.083 0.00690 -12.03 <.0001
a15 -0.13409 0.00680 -19.73 <.0001
a16 -0.11061 0.00683 -16.20 <.0001
a17 -0.08814 0.00645 -13.66 <.0001
a18 -0.09156 0.00608 -15.06 <.0001
a19 -0.04773 0.00541 -8.83 <.0001
a20 -0.06393 0.00492 -13.00 <.0001
lallojgalpc_l1 0.662 0.0810 8.17 <.0001 AR(lallojgalpc)
lallojgalpc lag1
parameter
lallojgalpc_l2 0.333129 0.0813 4.10 <.0001 AR(lallojgalpc)
lallojgalpc lag2
parameter
OLS Estimation Summary
Data Set Options
DATA= ORANGE_JUICE_FDOC_DATA
Minimization Summary
Parameters Estimated 20
Method Gauss
Iterations 10
Subiterations 2
Average Subiterations 0.2
Final Convergence Criteria
R 0.000968
PPC(a0) 0.001352
RPC(a2) 0.007989
Object 0.000022
Trace(S) 0.000244
Objective Value 0.000214
Observations Processed
Read 165
Solved 165
Used 161
Missing 4 30
Nonlinear OLS Summary of Residual Errors
DF DF
Equation Model Error SSE MSE
lallojgalpc 20 141 0.0344 0.000244
Adj Durbin
Root MSE R-Square R-Sq Watson
31
Root MSE R-Square R-Sq Watson
0.0156 0.9527 0.9463 2.1073
Nonlinear OLS Parameter Estimates
Approx Approx
Parameter Estimate Std Err t Value Pr > |t| Label
a0 1.579064 1.7490 0.90 0.3682
a1 -0.81986 0.0727 -11.28 <.0001
a2 0.389325 0.1027 3.79 0.0002
a3 -0.25878 0.1850 -1.40 0.1641
a4 0.037626 0.0155 2.42 0.0168
a5 0.001734 0.000987 1.76 0.0812
a6 1.058429 0.2088 5.07 <.0001
a10 0.043751 0.00521 8.41 <.0001
a11 -0.10001 0.00533 -18.78 <.0001
a12 -0.0148 0.00598 -2.47 0.0146
a5 = wo, and a6=λ, but since λ>1, the
geometric lag specification is
32
a12 -0.0148 0.00598 -2.47 0.0146
a13 -0.0881 0.00658 -13.39 <.0001
a14 -0.08289 0.00679 -12.21 <.0001
a15 -0.13322 0.00670 -19.89 <.0001
a16 -0.10975 0.00671 -16.37 <.0001
a17 -0.08795 0.00640 -13.74 <.0001
a18 -0.09079 0.00594 -15.30 <.0001
a19 -0.04783 0.00532 -9.00 <.0001
a20 -0.06275 0.00468 -13.42 <.0001
lallojgalpc_l1 0.660166 0.0801 8.24 <.0001 AR(lallojgalpc)
lallojgalpc lag1
parameter
lallojgalpc_l2 0.334802 0.0804 4.16 <.0001 AR(lallojgalpc)
lallojgalpc lag2
parameter
specification is not appropriate.
We assume that the lag weights can be specified by a continuous function and approximated by a polynomial function.
We must specify:
(A) the length of the lag
(B) degree of the polynomial
Polynomial Distributed Lags(development attributed to Shirley Almon)
desirable to have both of these fairly small.
We have flexibility; however:
• degree of the polynomial<the number of terms in dis tributed lag minus one, or else we get no reduction in the n umber of parameters to be estimated.
• possibility exists for endpoint restrictions.
Almon lag polynomials
.iC...iCiCCW nn
2210i ++++=
33
Y w X w X w X w X
Assume that
w c
w c c c
t t t t t t
o
= + + + + + + ∈
== + +
− − −α 0 1 1 2 2 6 6
0
1 0 1 2
...
Example:
w c c c
w c c c
w c c c
w c c c
w c c c
w c c c
= + += + += + += + += + += + +
1 0 1 2
2 0 1 2
3 0 1 2
4 0 1 2
5 0 1 2
6 0 1 2
2 4
3 9
4 16
5 25
6 3634
Endpoint Restrictions:
(1) Head Restriction w -1 = 0
(2) Tail Restriction w = 0
By Substitution,
(or by GLS if necessary to account for serial corre lationOnly 3 parameters to be estimated
[ ] [ ][ ] t6t2t1t2
6t2t1t16t1tt0t
X36...X4XCX6...X2XCX...XXCY
ε+++++++++++++α=
−−−
−−−−−
OLSby ,C ,C ,C Estimate 210
(2) Tail Restriction w 7 = 0
w c c c c c c
w c c c c c c− = − + = ⇒ = +
= + + = ⇒ = − −1 0 1 2 1 0 2
7 0 1 2 0 1 2
0
7 49 0 7 49
or both head & tail restrictions,
c c c c c c
c c
c c c c
1 1 2 2 1 2
1 2
1 2 0 2
7 49 7 48
8 48
6 7
= − − + = − −= −
= − = −
only need to estimate c 235
The polynomial lag model was used by Almon to estimate the relationship between current capital expenditures and current and past capital appropriations in the United States Manufacturing Industries. The degree of the polynomial in each case was 4, but the length of the lag was taken to be different for different industries. The data estimation was given by the quarterly observations for the years 1953-1961. The model was specified
Example:
observations for the years 1953-1961. The model was specified as:
where Y represents capital expenditures, the S’s represent seasonal dummy variables, and the X’s represent capital appropriations. The weights were restricted by the conditions that w-1=0 and w m+1=0, but they were not required to add up to unity.
tmtmtttttt XWXwXwSSSSY ∈++++++++= −− ...110443322111 αααα
36
The result for “All Manufacturing Industries” was as follows:
ttttt
ttttttttt
XXXX
XXXXSSSSY
∈+++++
+++++−+−=
−−−−
−−−
7654
)023.0(3
)013.0(2
)016.0(1
)023.0(4321
053.0105.0146.0167.0
165.0141.0099.0048.03205013283
As can be seen, the chosen length of the lag in th is case was 7 periods. The weights add up to 0.922.
Mean lag = 3.54
ttttt XXXX ∈+++++ −−−−)024.0(
7)016.0(
6)013.0(
5)023.0(
4 053.0105.0146.0167.0
37
38
39
PDLREG ProcedurePROC PDLREG can include any number of explanatory
variables with distribution lags and any number of explanatory variables without lag distributions (called covariates).
The PDLREG procedure supports endpoint restrictions. This procedure also allows the imposition of linear restrictions on the parameter estimates for the covariates.
40
the parameter estimates for the covariates.The PDLREG procedure allows the specification of a minimum
degree and a maximum degree for the lag distribution polynomial, and the procedure fits polynomials for all degrees in the specified range.
The PDLREG procedure also conducts tests for serial correlation, and allows the specification of any order autoregressive error model. In addition, the procedure allows for the specification of several different estimation methods for the autoregressive model.
The Syntax for the Specification of a Polynomial
Distributed Lag (PDL) for PROC PDLREG is as
follows:
Variable (length, degree, minimum-degree, constraint)
� Length – specifies the number of lags of the variable to include in the lag distribution.
41
the lag distribution.� Degree – specifies the maximum degree of the distribution
polynomial. If not specified, the degree defaults to the lag length.� Minimum-degree – specifies the minimum degree of the
polynomial. By default, minimum degree is the same as degree.� Constraint – specifies endpoint restrictions on the polynomial.
The value of constraint can be FIRST, LAST, or BOTH. If a value is not specified, there are no endpoint restrictions.
Section 11.5Section 11.5
SAMPLE PROBLEM:
Polynomial Distributed Lag
options nodate;run;
*********************************************************************************GLS procedure to run a polynomial distributed lag *********************************************************************************;
* correction for serial correlation; Proc pdlreg data=Orange_Juice_FDOC_Data;*3 lags and 2nd degree polynomial with both end point restrictions;
model lallojgalpc = lrallojprice lrallgfjprice lrpcdpi sc0996
43
model lallojgalpc = lrallojprice lrallgfjprice lrpcdpi sc0996 lrojfdocadexp(3,2,,both) m1-m11 / nlag=2 method=ml; *4 lags and 2nd degree polynomial with both end point restrictions;
model lallojgalpc = lrallojprice lrallgfjprice lrpcdpi sc0996 lrojfdocadexp(4,2,,both) m1-m11 / nlag=2 method=ml; *5 lags and 2nd degree polynomial with both end point restrictions;
model lallojgalpc = lrallojprice lrallgfjprice lrpcdpi sc0996 lrojfdocadexp(5,2,,both) m1-m11 / nlag=2 method=ml; *6 lags and 2nd degree polynomial with both end point restrictions;
model lallojgalpc = lrallojprice lrallgfjprice lrpcdpi sc0996 lrojfdocadexp(6,2,,both) m1-m11 / nlag=2 method=ml;
*7 lags and 2nd degree polynomial with both end point restrictions;
model lallojgalpc = lrallojprice lrallgfjprice lrpcdpi sc0996
lrojfdocadexp(7,2,,both)
m1-m11 / nlag=2 method=ml;
*8 lags and 2nd degree polynomial with both end point restrictions;
model lallojgalpc = lrallojprice lrallgfjprice lrpcdpi sc0996
lrojfdocadexp(8,2,,both) m1-m11 / nlag=2 method=ml; lrojfdocadexp(8,2,,both) m1-m11 / nlag=2 method=ml;
*9 lags and 2nd degree polynomial with both end point restrictions;
model lallojgalpc = lrallojprice lrallgfjprice lrpcdpi sc0996
lrojfdocadexp(9,2,,both) m1-m11 / nlag=2 method=ml;
*10 lags and 2nd degree polynomial with both end point restrictions;
model lallojgalpc = lrallojprice lrallgfjprice lrpcdpi sc0996
lrojfdocadexp(10,2,,both) m1-m11 / nlag=2 method=ml;
44
Maximum Likelihood Estimation ProcedureAR(1), AR(2) Correction
Lag Length
RMSE SBC AIC MAE MAPE R 2
3 0.0156 -809.34 -868.00 0.0111 0.8077 0.9522
4 0.0155 -805.49 -864.04 0.0109 0.7977 0.9530
5 0.0157 -796.23 -854.66 0.0112 0.8125 0.9521
45
5 0.0157 -796.23 -854.66 0.0112 0.8125 0.9521
6 0.0158 -788.72 -847.03 0.0113 0.8211 0.9517
7 0.0158 -783.09 -841.28 0.0114 0.8293 0.9518
8 0.0160 -775.07 -833.14 0.0115 0.8376 0.9513
9 0.0161 -768.07 -826.02 0.0116 0.8451 0.9511
10 0.0161 -761.66 -819.49 0.0117 0.8513 0.9510
Lag Lengths of three or four are optimal.
FDOC Orange Juice Problem
The PDLREG Procedure
Dependent Variable lallojgalpc
Lag Length of Three Months for Advertising and Promotion
Ordinary Least Squares Estimates Ordinary Least Squares Estimates
SSE 0.11591805 DFE 145
MSE 0.0007994 Root MSE 0.02827
SBC -627.05461 AIC -679.54375
MAE 0.0197688 AICC -675.29375
MAPE 1.42931379 Regress R-Square 0.8408
Durbin-Watson 0.4361 Total R-Square 0.8408
46
Standard Approx
Variable DF Estimate Error t Value Pr > |t|
Intercept 1 1.1278 0.9049 1.25 0.2147
lrallojprice 1 -0.3823 0.0320 -11.93 <.0001
lrallgfjprice 1 0.2992 0.0527 5.67 <.0001
lrpcdpi 1 -0.2599 0.0961 -2.70 0.0077
SC0996 1 0.0462 0.009587 4.82 <.0001
lrojfdocadexp**0 1 0.004549 0.001372 3.31 0.0012
lrojfdocadexp**1 1 -1E-18 0 -Infty <.0001
lrojfdocadexp**2 1 -0.000910 0.000274 -3.31 0.0012
47
lrojfdocadexp**2 1 -0.000910 0.000274 -3.31 0.0012
m1 1 0.0413 0.0112 3.71 0.0003
m2 1 -0.1072 0.0112 -9.61 <.0001
m3 1 -0.0246 0.0112 -2.20 0.0297
m4 1 -0.0937 0.0110 -8.51 <.0001
m5 1 -0.0907 0.0110 -8.26 <.0001
m6 1 -0.1427 0.0110 -13.01 <.0001
m7 1 -0.1173 0.0110 -10.70 <.0001
m8 1 -0.0927 0.0110 -8.43 <.0001
m9 1 -0.0945 0.0110 -8.62 <.0001
m10 1 -0.0499 0.0112 -4.48 <.0001
m11 1 -0.0670 0.0111 -6.02 <.0001
o 1 2co, c1, and c2
Tests of Endpoint Restrictions
Standard Approx
Restriction DF L Value Error t Value Pr > |t|
lrojfdocadexp(-1) -1 -0.2506 0.1662 -1.51 0.1320
lrojfdocadexp(4) -1 0.2606 0.1655 1.57 0.1158
Estimate of Lag Distribution Estimate of Lag Distribution
Standard Approx
Variable Estimate Error t Value Pr > |t|
lrojfdocadexp(0) 0.001819 0.000549 3.31 0.0012
lrojfdocadexp(1) 0.002729 0.000823 3.31 0.0012
lrojfdocadexp(2) 0.002729 0.000823 3.31 0.0012
lrojfdocadexp(3) 0.001819 0.000549 3.31 0.0012
48
wo=0.001819; w1= 0.002729, w2= 0.002729; and w3= 0.001819
The PDLREG Procedure
Maximum Likelihood Estimates
SSE 0.03476417 DFE 143
MSE 0.0002431 Root MSE 0.01559
SBC -809.33613 AIC -868.00046
49
SBC -809.33613 AIC -868.00046
MAE 0.01107909 AICC -862.64835
MAPE 0.80770868 Regress R-Square 0.9373
Durbin-Watson 1.8710 Total R-Square 0.9522
Standard Approx
Variable DF Estimate Error t Value Pr > |t|
Intercept 1 1.6456 1.6799 0.98 0.3289
lrallojprice 1 -0.8153 0.0730 -11.16 <.0001
lrallgfjprice 1 0.3720 0.1025 3.63 0.0004
lrpcdpi 1 -0.2699 0.1766 -1.53 0.1286
SC0996 1 0.0380 0.0154 2.47 0.0146
lrojfdocadexp**0 1 0.003564 0.001386 2.57 0.0112
lrojfdocadexp**1 1 -2.8E-18 0 -Infty <.0001
lrojfdocadexp**2 1 -0.000713 0.000277 -2.57 0.0112
m1 1 0.0436 0.005156 8.46 <.0001
50
m1 1 0.0436 0.005156 8.46 <.0001
m2 1 -0.0996 0.005357 -18.60 <.0001
m3 1 -0.0149 0.006070 -2.45 0.0156
m4 1 -0.0860 0.006454 -13.33 <.0001
m5 1 -0.0806 0.006613 -12.19 <.0001
m6 1 -0.1321 0.006652 -19.86 <.0001
m7 1 -0.1081 0.006559 -16.48 <.0001
m8 1 -0.0868 0.006370 -13.62 <.0001
m9 1 -0.0905 0.005973 -15.16 <.0001
m10 1 -0.0480 0.005363 -8.94 <.0001
m11 1 -0.0639 0.004671 -13.67 <.0001
AR1 1 -0.6509 0.0797 -8.16 <.0001
AR2 1 -0.3182 0.0799 -3.98 0.0001
Tests of Endpoint Restrictions
Standard Approx
Restriction DF L Value Error t Value Pr > |t|
lrojfdocadexp(-1) -1 -0.0571 0.0928 -0.62 0.5402
lrojfdocadexp(4) -1 0.0991 0.0917 1.08 0.2814
Estimate of Lag Distribution
51
Estimate of Lag Distribution
Standard Approx
Variable Estimate Error t Value Pr > |t|
lrojfdocadexp(0) 0.001426 0.000554 2.57 0.0112
lrojfdocadexp(1) 0.002138 0.000832 2.57 0.0112
lrojfdocadexp(2) 0.002138 0.000832 2.57 0.0112
lrojfdocadexp(3) 0.001426 0.000554 2.57 0.0112
sum 0.007128 (Long-Run)
The PDLREG Procedure
Dependent Variable lallojgalpc
Lag Length of Four Months for Advertising and Promotion
Ordinary Least Squares Estimates
SSE 0.1078914 DFE 144
MSE 0.0007492 Root MSE 0.02737
52
MSE 0.0007492 Root MSE 0.02737
SBC -633.31147 AIC -685.69534
MAE 0.01904292 AICC -681.41562
MAPE 1.37727724 Regress R-Square 0.8517
Durbin-Watson 0.4576 Total R-Square 0.8517
Standard Approx
Variable DF Estimate Error t Value Pr > |t|
Intercept 1 0.9254 0.8824 1.05 0.2960
lrallojprice 1 -0.3903 0.0311 -12.54 <.0001
lrallgfjprice 1 0.3157 0.0513 6.15 <.0001
lrpcdpi 1 -0.2413 0.0936 -2.58 0.0109
SC0996 1 0.0469 0.009293 5.04 <.0001
lrojfdocadexp**0 1 0.004967 0.001269 3.92 0.0001
lrojfdocadexp**1 1 7.35E-19 0 Infty <.0001
lrojfdocadexp**2 1 -0.001187 0.000303 -3.92 0.0001
53
lrojfdocadexp**2 1 -0.001187 0.000303 -3.92 0.0001
m1 1 0.0418 0.0108 3.87 0.0002
m2 1 -0.1076 0.0108 -9.96 <.0001
m3 1 -0.0248 0.0108 -2.29 0.0235
m4 1 -0.1010 0.0109 -9.27 <.0001
m5 1 -0.0927 0.0107 -8.68 <.0001
m6 1 -0.1439 0.0106 -13.53 <.0001
m7 1 -0.1191 0.0106 -11.22 <.0001
m8 1 -0.0938 0.0106 -8.83 <.0001
m9 1 -0.0949 0.0106 -8.96 <.0001
m10 1 -0.0496 0.0108 -4.59 <.0001
m11 1 -0.0663 0.0108 -6.15 <.0001
Tests of Endpoint Restrictions
Standard Approx
Restriction DF L Value Error t Value Pr > |t|
lrojfdocadexp(-1) -1 -0.2915 0.2237 -1.30 0.1935
lrojfdocadexp(5) -1 0.2714 0.2223 1.22 0.2235
The PDLREG Procedure
54
Estimate of Lag Distribution
Standard Approx
Variable Estimate Error t Value Pr > |t|
lrojfdocadexp(0) 0.001587 0.000405 3.92 0.0001
lrojfdocadexp(1) 0.002538 0.000648 3.92 0.0001
lrojfdocadexp(2) 0.002856 0.000729 3.92 0.0001
lrojfdocadexp(3) 0.002538 0.000648 3.92 0.0001
lrojfdocadexp(4) 0.001587 0.000405 3.92 0.0001
The PDLREG Procedure
Maximum Likelihood Estimates
SSE 0.0342103 DFE 142
MSE 0.0002409 Root MSE 0.01552
SBC -805.48903 AIC -864.03572
MAE 0.01094611 AICC -858.64565
MAPE 0.79770193 Regress R-Square 0.9381 MAPE 0.79770193 Regress R-Square 0.9381
Durbin-Watson 1.8743 Total R-Square 0.9530
55
Standard Approx
Variable DF Estimate Error t Value Pr > |t|
Intercept 1 1.6988 1.6567 1.03 0.3069
lrallojprice 1 -0.8064 0.0729 -11.06 <.0001
lrallgfjprice 1 0.3772 0.1020 3.70 0.0003
lrpcdpi 1 -0.2790 0.1743 -1.60 0.1116
SC0996 1 0.0374 0.0153 2.45 0.0155
lrojfdocadexp**0 1 0.004243 0.001419 2.99 0.0033
lrojfdocadexp**1 1 -3.87E-19 0 -Infty <.0001
lrojfdocadexp**2 1 -0.001014 0.000339 -2.99 0.0033
m1 1 0.0436 0.005120 8.51 <.0001 m1 1 0.0436 0.005120 8.51 <.0001
m2 1 -0.1005 0.005357 -18.75 <.0001
m3 1 -0.0156 0.006048 -2.59 0.0107
m4 1 -0.0883 0.006595 -13.39 <.0001
m5 1 -0.0828 0.006732 -12.30 <.0001
m6 1 -0.1336 0.006695 -19.95 <.0001
m7 1 -0.1098 0.006568 -16.72 <.0001
m8 1 -0.0878 0.006324 -13.88 <.0001
m9 1 -0.0908 0.005933 -15.30 <.0001
m10 1 -0.0478 0.005339 -8.96 <.0001
m11 1 -0.0635 0.004660 -13.62 <.0001
AR1 1 -0.6472 0.0799 -8.10 <.0001
AR2 1 -0.3202 0.0802 -3.99 0.0001
56
Tests of Endpoint Restrictions
Standard Approx
Restriction DF L Value Error t Value Pr > |t|
lrojfdocadexp(-1) -1 -0.0282 0.1143 -0.25 0.8059
lrojfdocadexp(5) -1 0.0405 0.1140 0.36 0.7236
Estimate of Lag Distribution Estimate of Lag Distribution
Standard Approx
Variable Estimate Error t Value Pr > |t|
lrojfdocadexp(0) 0.001355 0.000453 2.99 0.0033
lrojfdocadexp(1) 0.002169 0.000725 2.99 0.0033
lrojfdocadexp(2) 0.002440 0.000816 2.99 0.0033
lrojfdocadexp(3) 0.002169 0.000725 2.99 0.0033
lrojfdocadexp(4) 0.001355 0.000453 2.99 0.0033
57
Sum = 0.009488 LR advertising elasticity
Section 11.6Section 11.6
The Partial Adjustment
Model
uQYPQ
Q)1(YaPaaQ
YaPaaQ
QQ)QQ)(/1(
10)QQ(QQQ
t1t3t2t10t
t1tt2t10t
tt2t10*t
*t1t1tt
1t*tt1tt
+β+β+β+β=γε+γ−+γ+γ+γ=
ε+++=
→γ
=+−γ
<γ<−γ=∆=−
−
−
−−
−−
Coefficient or Elasticity of Adjustment
Partial Adjustment
Model – Nerlove (1958)
Q
Q
a
1 Sinceˆ1ˆ
t
*t
33
⇒
⇒
β
γ−=ββ−=γ
Coefficients LR CoefficientsCoefficients SR Coefficients
Quantity demanded in Long-Run Equilibrium
(Desired Level)Current Quantity Demanded
59
γ Represents the Proportion of Adjustment Made Toward Long-Run Equilibrium in Various Time
Periods
)1(2
1
Adjustment of ProportionPeriod Time
γ−γγ
1s
3
2
)1(S
::
)1(4
)1(3
)1(2
−γ−γ
γ−γγ−γγ−γ
60
Section 11.7Section 11.7
SAMPLE PROBLEM:
Partial Adjustment Model
*************************************************************************GLS procedure to run a partial adjustment model **************************************************************************;
* no correction for serial correlation is necessary from the Durbin h-test; Durbin h-test; proc autoreg data=Orange_Juice_FDOC_Data;
model lallojgalpc=lrallojprice lrallgfjprice lrpcdpi sc0996 lrojfdocadexp m1-m11
laglojgalpc / lagdep=laglojgalpc;
62
The AUTOREG Procedure
Dependent Variable lallojgalpc
Ordinary Least Squares Estimates
SSE 0.05803079 DFE 146
MSE 0.0003975 Root MSE 0.01994
SBC -746.04083 AIC -801.83843
MAE 0.01326703 AICC -797.12119
63
SBC -746.04083 AIC -801.83843
MAE 0.01326703 AICC -797.12119
MAPE 0.96889253 Regress R-Square 0.9219
Total R-Square 0.9219
Miscellaneous Statistics
Statistic Value Prob Label
Durbin h 1.4128 0.0789 Pr > h
NOTE: No serial correlation
Standard Approx
Variable DF Estimate Error t Value Pr > |t|
Intercept 1 1.1001 0.6328 1.74 0.0842
lrallojprice 1 -0.1350 0.0274 -4.93 <.0001
lrallgfjprice 1 0.1357 0.0380 3.57 0.0005
lrpcdpi 1 -0.1547 0.0680 -2.28 0.0243
SC0996 1 0.0214 0.006909 3.10 0.0023
lrojfdocadexp 1 0.002706 0.001483 1.82 0.0701
m1 1 -0.0111 0.008701 -1.28 0.2034
m2 1 -0.1793 0.009578 -18.72 <.0001
m3 1 0.007710 0.007833 0.98 0.3266
64
m3 1 0.007710 0.007833 0.98 0.3266
m4 1 -0.1312 0.008225 -15.95 <.0001
m5 1 -0.0736 0.007787 -9.45 <.0001
m6 1 -0.1262 0.007804 -16.17 <.0001
m7 1 -0.0637 0.008670 -7.35 <.0001
m8 1 -0.0569 0.008215 -6.92 <.0001
m9 1 -0.0730 0.007929 -9.21 <.0001
m10 1 -0.0309 0.007994 -3.86 0.0002
m11 1 -0.0777 0.007947 -9.77 <.0001
laglojgalpc 1 0.7159 0.0497 14.40 <.0001
2841.07159.01ˆ =−=γ
Information Gleaned from the Estimation of the Partial Adjustment Model
SR Elasticity LR ElasticityOrange Juice -0.1350 -0.4752
Grapefruit Juice 0.1357 0.4776
65
2841.07159.01ˆ =−=γ
Grapefruit Juice 0.1357 0.4776
Advertising 0.002706 0.0095248
Proportion of Adjustment to LR Equilibrium in
Various Time PeriodsTime Period Proportion of Adjustment
1 0.2841
2 0.2034
3 0.1456
4 0.1042
5 0.0746
The length of time to adjust to LR
66
5 0.0746
6 0.0534
7 0.0382
8 0.0274
9 0.0196
10 0.0140
11 0.0100
12 0.0072
sum 0.9819
adjust to LR equilibrium is roughly 1 year (12 months). Roughly 98% of the adjustment to LR equilibrium takes place after one year.