( iiple'r 2 These cut-off points are fairly arbitrary, but the index does give an overall measurement which can be used to compare countries, and monitor the progress of an individual country over time. Much, of course, depends on the accuracy of the data available and there iL; considerable extrapolation from income statistics. Table 2.8 shows the AHFSI for a selection of countries whose AHFSI was originally medium or below and dropped during the period 1988-90 to 1991-93. Table 2.8 AHFSI Values for Selected Countries Country AHFSI AHFSI AHFSI 1993 1988-1990 1991-1993 Guatemala 76.0 70.9 72.0 Congo 75.9 72.6 70.2 Cambodia 72.6 69.3 71.1 Tanzania 72.0 67.9 67.0 Haiti 67.3 26.5 28.6 Rwanda 66.3 62.4 57.0 Zambia 71.4 62.1 76.7 Afghanistan 37.6 31.2 31.4 Mozambique 41.3 34.5 34.5 Somalia 43.4 35.8 37.5 Source: FAO There is not, as yet, a great deal of experience in the use of these indicators, and some of the values shown in Table 2.8, for example for Haiti, would seem to indicate a considerable variation in value. However, the AHFSI goes a long way to allowing a preliminary identification of a country with considerable food security problems, which need a closer analysis for policy assistance. The index is likely to prove particularly useful in assessing requests for food and other emergency assistance. 5. Assessing the Nutrition Situation at Different Levels of Aggregation This chapter has discussed a number of different indicators at different levels of aggregation. They each can give useful information on different aspects of the food system and potential food security problems, but the analyst has to be careful to interpret the results sensibly and not to make unreasonable inferences from the data available. Food Balance Sheet information gives a highly aggregated picture of food flows through the system, culminating in an estimate of average calorie and protein availability at a national level. This can be compared with estimates of average RNIs (reference nutrient intakes) for the population to assess the adequacy of the food supply. However, although RNIs give an estimate of the minimum food supply necessary if food were distributed - 56-