Estimating Calorie Poverty Rates Through Regression

Abstract

In this paper we assume a tri-variate distribution of the nutrient intake (y), say calorie intake, the income (x) and the nutrient norm (z) of the households, which leads to linear or log-linear regression equations depending on the type of joint distribution assumed for the purpose of estimation. Nutrient norm takes care of age-sex composition of a household. The probability that the household consumes less than the prescribed norm can be computed from the regression result. This probability can be regarded as the estimated value of the calorie-poverty rate when taken in aggregate. In practice, since income data are not available, the per-capita total expenditure of the household is taken as a proxy to per-capita income and regression is run for different expenditure groups. We have applied this technique to the 61st round data collected by National Sample Survey Organization (NSSO), India, on calorie intakes. The estimates of the poverty rates found by this method are unbelievably high and call for further investigations. The reasons for getting such high estimates are discussed and a modification of the estimates is suggested in the paper. The modification leads to reasonable estimates of the poverty rates.

Appendix: The Detail Methodology Toward Finding Poverty Rate

The conventional Method of finding the poverty lines is divided into few steps as follows.

• (i) Each member in a household is put in the respective group according to the pre-assigned age–sex groups and the activity status of adult members prepared for this purpose. In addition to it, the status of pregnancy of female members may also be considered. For each age–sex–activity status group, there is also a pre-assigned calorie requirement called calorie norm. Calorie norm of a household is determined by adding the calorie norm of each member of the household.

• (ii) For a given region, the proportion of population in each age–sex–activity status group is found. The average calorie norm of the region (may be termed as calorie line) is found by taking the weighted mean of the calorie norms of each category of members where weight is taken as proportional to the total population in that category. It is assumed that the poverty line of the region is a function of the calorie line. The poverty line of the region is thus based on this calorie line. The regions taken in India are the rural and urban sectors of each state. Overall calorie lines of rural and urban India are also found.

• (iii) Actual calorie consumption of the household is calculated by adding the calorie of each food item consumed by the household. This is done by using the calorie conversion factor of each item which is defined as the calorie content of one unit of the item. Naturally to find the calorie intake of the household, one should have data on quantities of food items consumed by the household.

• (iv) It is assumed that calorie intake or more precisely per capita calorie intake of a household is directly related with the per capita food expenditure and in turn with the per capita total expenditure of the household. In practice, the two steps, i.e., finding the relation between per capita calorie intake and the per capita food expenditure and then between per capita food expenditure and the per capita total expenditure are merged and only the relation between per capita calorie intake and the per capita total expenditure is found. The relation is established for different expenditure groups to make it as realistic as possible. The poverty line is the per capita total expenditure which corresponds to the calorie norm of the concerned population. This may be done for each state separately for rural and urban regions. Since per capita calorie intake is viewed as a function of the per capita total expenditure, the poverty line is found by inverse interpolation method.

• (v) It should be noted here that the official poverty line, till 2009, was found by projecting the poverty line from the base year poverty line to the current year poverty line using the relevant price indices. The base year poverty rates were found by a method which is similar to the conventional method.