Chapter I Transitory food insecurity may lead to chronic food insecurity, depending on how severe it is and how frequently it occurs. If a household suffers two drought years in a row. and is forced to sell some of its assets to survive, then it may move from a situation of transitory food insecurity to one of chronic food insecurity. 1.3 Entitlements The use that households can make of the resources available to them, as well as the level of those resources, depends to some extent on the nature of the environment within which they operate, and the specific forms of the institutions which regulate the relations between the various economic agents. An approach to analysing the problem which takes these different elements into account is known as analysing entitlements, developed by Amartya Sen. He defines entitlements as "the set of alternative commodity bundles that a person can command in a society using the totality of rights and opportunities that he or she faces", in other words, what a person can produce, buy or borrow, given what they own and what social and state regulations allow them to do with that. He identifies four main categories of entitlement: 1. Trade-based entitlement, which describes what an individual can buy with the commodities and cash they own. 2. Production-based entitlement, which describes the right to own what one produces with one's own resources. 3. Own-labour entitlement, which describes the sale of one's own labour power, and the resulting trade-based entitlements. 4. Inheritance and transfer entitlement, which refers to the right to own what is willingly given by others as remittances, gifts or bequests, as well as transfers from the state such as social security, pensions and food distribution. All these entitlements give an incontrol over resources which Lhy can use within the rules and regulations laid down by society, to satisfy their needs, including the very basic need of food. This goes rather further than a purely economic analysis of prices and income, insofar as it allows for consideration of both traditional community minstitutiolls, such as communal granaries or access to common grazing land and state institutions such as feeding programmes, when analysing how people meet their food requirements. 1.4 Vulnerable groups Until now, the level of aggregation of food security has been discussed, as has the time factor, but now the risk factors which create food insecurity must come into consideration. There are two approaches which can be taken to this. The first is to look at the characteristics of the vulnerable groups in a society. The second is to examine the sources of risk to their entitlements. Both approaches give useful insights: the first helps identify vulnerability; the second illustrates how that vulnerability may change over time. The food insecure are not confined to those who have food deficient diets at a given point in time. They include those whose access to food is insecure or vulnerable, those who are in danger of inadequate diets.