Overview: interpreting anthropometric data in a food security
context
Slide 2
Aims of this presentation: 1. To show that, with some
exceptions, it is only possible to interpret anthropometric survey
data if the food security context is understood. 2. To open the
discussion on food security: a much used term but one which is used
in different ways by different organisations, and on which as yet
there is no agreed method or best practice.
Slide 3
The exceptions: Anthropometric survey results can usually be
interpreted without information on food security: Where repeated
surveys are used to monitor trends. In the (rare) situation where
there is complete control of food security e.g. the population is
wholly dependent on food aid, or the situation is so bad as to
demand that food is supplied.
Slide 4
Prevalence of malnutrition in Mchinji, Malawi, December 2001.
Weight-for-height 11.8 % (7.2-16.4%) 3.8 % (1.9% - 5.7%) < - 2
SD < -3SD or oedema
Slide 5
The estimate of malnutrition is much higher than the reference
values: it is known that in 2001 maize production in Malawi fell by
20-30% & maize prices have increased. The findings could be
interpreted to mean that: people are short of food, nutritional
status has declined and food aid should be supplied. the findings
are unexceptional - oedema rates tend to rise at the end of each
year. Problems with interpretation: abnormal or not, it will take
2-3 months to import food in quantity. As the next harvest is due
in March 2002, it is reasonable not to take any action.
Slide 6
Food security: what do we need to know in order to interpret
anthropometric surveys? How has an event e.g. crop failure, price
change, affected peoples ability to get food? How is peoples
ability to get food likely to evolve in future?
Slide 7
The anthropometric outcome depends (disease aside) on people's
access to food, not on the aggregate supply of food. In practice
peoples ability to acquire food depends partly on the overall
supply: but even if food supply is adequate, or in gross surplus,
it does not mean that all people have access to it. People can and
do starve in countries that produce surpluses of food. Food supply
or access to food?
Slide 8
Food security Access at all times to enough food of a
sufficient quality to ensure an active healthy life. World
Bank.
Slide 9
Best practice in food security? 1. Food balance & crop
based systems. 2. Indicator systems use proxy indicators of food
availability/access e.g prices, rainfall, crops. 4. Algorithmic
methods typically multivariate equations which seek to predict e.g.
nutritional status, from measures of livestock holdings, crop
production etc. 3. Livelihood systems. Systems which attempt to
understand and quantify the impact of a shock on the ability of
households to acquire food.
Slide 10
1. Food balance & crop based systems. Food availability
decline Failed crops = failure of food supply = hunger = a fall in
nutritional status. Food balance Production + stocks + imports -
losses - estimated population requirement = surplus or deficit
Slide 11
Problems with food balance/ crop methods: It is difficult/
impossible to estimate some variables accurately (e.g. crops,
privately held stocks, unofficial imports) There may be enough
food, but it may be in the wrong place. Fundamentally: in most
locations many people do not depend wholly, or at all, on crop
production for food - therefore they may be more or less unaffected
by crop failure.
Slide 12
Slide 13
2. Indicator methods Use easily collected/ obtained information
e.g. from routine government sources, which is thought to be a
proxy for food supply/ access There are few practical indicators
available (precipitation, crop production, prices). Data may be
dated, inaccurate or collected in unsuitable locations e.g. towns.
Indicators are not in fact always easy to collect. Problems:
Slide 14
Slide 15
Indicators can only be interpreted if the relationship between
the indicator and peoples economy is known. e.g. If a household
does not depend on the market for food, or has no cash, an increase
in the price of food may be irrelevant.
Slide 16
3. Livelihood methods - the household economy approach: Based
on: observed sources of household cash and food income: within
defined populations, usually of households. within populations by
wealth group e.g. poor, better off The aim is to calculate the
ability of households to maintain their food access in the face of
a shock and the relationship between households (e.g. gift), and
between households and the wider context - markets, wild foods
Slide 17
Slide 18
Problems with the Household Economy Approach: Requires data
collection: not all agencies have the people/ skills/ cash to do
this. Advantages: 1. It works. In a recent review of all (14) SC UK
cases where a prediction was made and information was available on
the outcome, the prediction and outcome were consistent. 2. It also
gives an estimate of who will be affected, how severely they will
be affected & when they will be affected.
Slide 19
December 2001. Nutritional status in Salima ( - 3SD) 9.3 %
(< -3 SD or oedema) 4.8%