Estimation on the Income Elasticity of Household Demand for Sweet Potatoes, Ipomoea batatas and Yams, Dioscorea Spp.

Abstract

The purpose of this study was to determine the income-consumption elasticity of household demand for sweet potatoes and yams in Puerto Rico, and to examine the nature and extent of the relationship between household consumption of these products and selected socio-economic variables. The analysis is based on data from a sample of 1,021 family records obtained by the method of personal interview from a cross-section of the population of Puerto Rico, during 1962. The method of analysis was the least-squares regression approach. Four basic models were fitted to the consumption data. The basic models initially included income as the only regressor, but were modified into multiple regression model by the subsequent addition of other variables. Analysis of all consuming households indicated an average income elasticity of demand for yams of 0.118 and coefficient of family size of 0.397. For sweet potatoes, the income elasticity and family size coefficients were 0.246 and 0.213 for all families, respectively. Low income elasticities show that even with dramatic improvements in real family income, the expected change in consumption duo to the income effect will be relatively small and largety overshadowed by anticipated decreases in average famity size in Puerto Rico. Variables other than family size and income had little or no measurable effect on household consumption of sweet potatoes and yams.