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 markets in the recent past, where adequate food is available and where most of the
 population have access to that food. An alternative definition would be that a country is food
 secure when all the individuals in the country are food secure. However, this definition,
 robust and clear though it may be, would exclude virtually all countries in the world. It is
 useful to have a less extreme definition which allows us to distinguish between, say, the
 United States which most people would feel was quite food secure and a country like Zaire,
 where food security poses greater problems.

 In the definition given above, changes in food security can be identified over time by rising
 prices. These will affect the poorest first, as they spend a higher proportion of their income
Con food (see Chapter 2). The absence of an imbalance between food demand and food supply
 does not mean that all households in the nation are food secure. It means that if they suffer
 from food insecurity it is because they lack entitlement to food, what economists would call
 effective demand. They have no way of expressing their full need for food in the
 marketplace.

 There are countries where the overall supply of food is clearly inadequate to mecl its citi/cns'
 needs, even if it were distributed entirely according to that need, rather than according to
 entitlement, or market demand. The analyst may wish to identify countries in this extreme
 situation, without in any way wishing to imply that other countries, which do not L. ll into
 this category provide food security for all its citizens.

 The household level of food security is probably the most important for the analyst. insofin
 as the household is the basic economic unit which determines the level of consumption hb
 the individual. In most analysis there is a presumption that income comes to the household
 as a whole, resource allocation decisions are made at the household level and household
 consumption is divided amongst its members in some relation to the needs of the individuals.
 As will be discussed in section 1.4, there are occasions when none of these assumptions arc
 valid. For the most part, however, they do reflect the basis on which economic activilv is
 organised, and the way that information is often collected. In general, throughotmt this %
 manual, the basic unit of analysis will be the household. At this level, households are /
 identified as food secure if their entitlements, or demand for food is greater than their needs,
 defined as the aggregation of individual requirements.

 At the individual level, the definition of food security is much more straightforward. Aln
 individual is food secure if his or her food consumption is always greater than need. as
 defined by physiological requirement. Consumption is determined by the claim th1eC
 individual has on household food resources. This may be affected by individual earnings and j
 assets, or by the individual's position in the household. It is certainly unusual for an
 individual's share of household food consumption to be determined solely by need.

 It is clear that food security at one level does not imply food security at a lower level of .,
 aggregation. A country which is food insecure will almost certainly contain groups of the
 population which are food secure, and many countries which are food secure at a national
 level will contain groups of the population who suffer from severe food inseecuril\. I ood
 security at the household level does not imply that all members of the household arc liod
 secure. A food insecure household may equally contain food secure members.