The effects of price on household demand for food and calories in poor countries: are our databases giving reliable estimates?

Food price policy relies heavily on estimated price elasticities of food demand to help balance the nutritional and economic objectives in poor countries. Economists use either unit values (ratios of household expenditure to quantity purchased) or community prices (enumerated from vendors in local markets) as proxies for market prices when estimating price elasticities with household survey data. Biases are believed to result from using unit values, due to measurement error and quality effects, but evidence on this issue is lacking and even less is known about community prices. This article provides an empirical evidence from Vietnam, which suggests that economists should exercise caution when estimating price elasticities from household surveys. A 14-food demand system is estimated alternatively with unit values or community prices, and the elasticity of calories with respect to rice prices is calculated. This elasticity is more than twice as large (?0.54 versus ?0.22) when community prices are used rather than unit values. Hence, conclusions about the nutritional effects of rice price increases appear sensitive to data choices made by economists. More generally, this discrepancy suggests that the household survey databases commonly used by economists may not provide reliable estimates.     

Quantile Regression Analysis of Predictors of Calorie Demand in India: An Implication for Sustainable Development Goals

This study examined predictors of households’ calorie demand using consumer expenditure survey data during the time frame of millennium development goals. It draws suggestions for achieving sustainable development goals to eliminate calorie-poverty. We used the log of per-capita calorie intake as the calorie demand. Endogeneity corrected quantile regression was applied to examine the distributional effect of predictors. Findings revealed calorie-monthly per-capita consumption expenditure (MPCE) elasticities were positively statistically significant across quantiles in rural-and urban-areas, but, contrary to traditional wisdom, elasticities are lower for calorie-poor than calorie-rich households. Dietary diversification of food items, relative food price, and share of medical-and education-expenditure were the main adverse drivers of calorie demand. Our results are robust to the under-reporting and measurement error. The policy implications are: (a) only focusing on pro-poor income enhancing strategies will not able to reduce calorie deprivation, it should be backed by imparting awareness about food choice and nutritional value of low price food items, (b) to implement necessary policy to maintain stable food inflation and effectively targeted food subsidy for calorie poor, (c) to adopt forward-looking medical-and education-policy such as free health and education facilities to all by enhancing public spending to revive the quality of public hospitals and educational institutions.

     

More or better? Measuring quality versus quantity in food consumption

As people become richer they get the opportunity of consuming more but also qualitatively better goods. This holds for a basic commodity like food as well. We investigate food consumption in Russia, taking into account both expenditure and nutrition value in terms of calories. We analyse how food consumption patterns change with increasing income by considering both “quantity Engel curves” and “quality Engel curves.” The former describe the functional dependence of calories consumed on total expenditure. The latter trace out the dependence of unit value per calorie on total expenditure. We compare income elasticities of quantity with income elasticities of unit value and quality. In Russian household survey data for years 2000–2002 the reaction of quality to income changes is significantly stronger than the reaction of quantity to income changes suggesting that Russian households tend to choose higher quality food items as income rises.     

Price hike of staple food,nutritional impact and consumption adjustment: evidence from the 2005–2010 rice price increase in rural Bangladesh

This paper studies the nutritional impact of the rice price increase between 2005 and 2010 on households in rural Bangladesh and their resulting adjustment in consumption of rice, non-rice food and non-food items. We compare net rice buyers, who suffer from a negative income effect, with self-sufficient households that do not suffer from any such effect. Our findings indicate that rural households in Bangladesh cope well with the surge in the domestic rice price as indicated by the absence of any effect on their calorie intake and dietary diversity. In fact, both types of households similarly change their consumption of rice, non-rice grain, pulses, protein, fruits and other items. Furthermore, we do not find any evidence of buyers’ switching towards low-quality items in a food group. In a separate analysis, we compare net rice sellers with self-sufficient households and arrive at a similar conclusion. In both cases, income plays a crucial role in the consumption of non-rice food and non-food items, indicating the importance of effective income support programs at the time of price shocks in staple food items.     

Nutrient consumption in India: Evidence from a village study

Adequate nutrition is generally regarded as a core dimension in any evaluation of well‐being. In the context of India, a country with a high prevalence of poor nutrition, there is a dearth of nutrition studies with adequate coverage and comparability. Using primary data on food consumption from a village in a poorer state of India, we study the consumption of five key nutrients, namely, calories, protein, carbohydrates, calcium and iron. Among the various determinants of nutrition, we find that expenditure has a significant impact on nutrition and the expenditure elasticity of nutrition is comparatively high for all the key nutrients. By correcting for potential endogeneity, we demonstrate a causal link from expenditure and food subsidy provided by the public distribution system to nutritional intake. There is some evidence that household characteristics such as household size and gender of the household head matter for nutrition; however, they are not robust under various specifications.     

The flexibility of household electricity demand over time

Empirical estimates of long run effects on residential electricity demand from changes in the electricity price are usually estimated by cross-sectional variation in the current stock of electric household appliances across households at a certain point in time. Here, we use a discrete–continuous approach modeling the long run effects by investments in new appliances. We apply the annual Norwegian Survey of Consumer Expenditure for the period 1975 to 1994 to estimate the short and long run own price elasticities in the two approaches. We find the estimated long run elasticity only slightly more price elastic than the short run. We also find that the long run elasticity does not differ significantly between the two approaches. The reason for both results is that, since there is no alternative source of energy for these appliances, there are no substitution effects.     

Food expenditures and household demographic composition in the US: a demand systems approach

Food expenditures and subsistence quantities of poverty status and non–poverty status US households are analysed within a Linear Expenditure System that postulates subsistence quantities to be linear combinations of demographic variables. Using the US Bureau of Labor Statistics' 1992 Consumer Expenditure Survey and Detailed Monthly Consumer Price Indices, this article obtains expenditure elasticities, own–price elasticities and subsistence quantities for each income group across nine broadly aggregated food commodity groups. Elasticity estimates and subsistence quantity estimates differ across income groups, supporting the premise that policies targeted at specific income groups should be based on the target group's elasticity estimates rather than average population elasticities. Parameter estimates are then used to simulate how subsistence quantities and own–price elasticities can be expected to vary according to the demographic composition of the household within a specific income group.     

Price, unit value, and quality demanded

Given the paucity of quality price data, it is common to rely on “unit value” (average expenditure per unit) as a proxy for price, but this is an imperfect proxy if households respond to price increases by substituting to lower quality goods. This paper draws on survey data that contain both unit value and price to estimate the severity of quality substitution in Indonesia, finding that it is prevalent. The paper next calculates price elasticities that correct for quality substitution, evaluating and ultimately rejecting a commonly used method for calculating price elasticities using only unit value data. Finally, it demonstrates that quality substitution can result in biased price elasticities even when price is perfectly observed.     

A Behavior‐Based Approach to the Estimation of Poverty in India

Estimates of poverty in India are crucial inputs for the understanding of world poverty, yet there is much disagreement about the numbers and the legitimacy of methods used to derive them. In this paper, we propose and justify an alternative approach to identify the poor, which uses the proportion of income spent on food. Our estimates have weaker data requirements than official methods, and they compare favorably with several validation tests. Most notably, households around our state poverty lines obtain their calories from similar sources, whereas this is not true of official poverty lines. We also find that rates of self‐reported hunger are higher in states that we classify as poor.     

Long-run relationships between labor and capital: Indirect evidence on the elasticity of substitution

This paper proposes an indirect method for making empirical inference on the elasticity of substitution between capital and labor. The idea is that estimates of the elasticity may be retrievable from theory derived behavioral equations, by conducting comparative statics with respect to this parameter. This approach is readily applicable to more realistic models than those which are commonly used to derive estimates of the substitution elasticity. It is demonstrated that the conventional approach does not yield sensible estimates on quarterly Finnish manufacturing data. By applying the indirect method, a long-run empirical relationship is found that is consistent with an elasticity of substitution below one.     

Optimal size of the government: the role of the elasticity of substitution

This paper analyzes the optimal fiscal policy in an endogenous growth model with productive public services. Government expenditure, which may be subject to different degrees of congestion, is financed by distortionary income taxation. The standard result on the equality between the growth-maximizing, welfare-maximizing and first-best income tax rates holds if and only if production is Cobb–Douglas or there is proportional congestion. With non-proportional (or in the absence of) congestion, the first-best income tax is lower than the (second-best) welfare-maximizing income tax which, in turn, is lower than the growth-maximizing income tax if the elasticity of substitution is below unity. Under mild conditions these relations are reversed if the elasticity of substitution is above unity. Intuition on these results is also provided.     

Measuring Price Responsiveness Under a Profit Maximization Framework

The distinguishing feature of the study is in using a globally flexible functional form that permits one to calculate different types of elasticities under both constant and variable output hypotheses. The Symmetric Generalized McFadden cost function alongwith the output supply condition form the basis of the econometric model. To measure inputsubstitutabilities, we used Alien-Uzawa, Morishima, and Shadow elasticities of substitution. Empirical results, based on 300 farm households from West Bengal, India, show that fertilizer is most price sensitive input. It is a gross substitute for manure and human labor but complement to bullock labor. Manure is a gross substitute for all the inputs whereas human labor is gross complement to bullock labor. Using the Morishima measure we find that the fertilizer and bullock labor are complements when the price of the latterchanges. Similar complementary relationship is found between bullock and human labor due to changes in the price of human labor. All other inputs are Morishima substitutes. The Shadow elasticity of substitution estimates indicate that all factors are substitutes. The estimate of returns to scale indicates the presence of diminishing returns to scale.

     

URBAN POVERTY IN CHINA AND ITS CONTRIBUTING FACTORS, 1986–2000

Food price increases and the introduction of radical social welfare and enterprise reforms during the 1990s generated significant changes in the lives of urban households in China. During this period urban poverty increased considerably. This paper uses household level data from 1986 to 2000 to examine what determines whether households fall below the poverty line over this period and investigates how the impact of these determinants has changed through time. We find that large households and households with more nonworking members are more likely to be poor, suggesting that perhaps the change from the old implicit price subsidies, based on household size, to an explicit income subsidy, based on employment, has worsened the position of large families. Further investigation into regional poverty variation indicates that over the 1986–93 period food price increases were also a major contributing factor. Between 1994 and 2000 the worsening of the economic situation of state sector employees contributed to the poverty increase.     

Food security in Kenya: Insights from a household food demand model

This paper evaluates the household food security situation in Kenya in terms of access to food. We apply a quadratic almost ideal demand system (QUAIDS) model to nationally representative household survey data from Kenya, and estimate and interpret price and expenditure elasticities as indicators of household sensitivity to market shocks. Our estimation results show positive expenditure elasticities, close to unity, while all compensated and uncompensated own-price elasticities are negative and smaller in magnitude. A complementary welfare analysis shows high compensated variations in the long run, ranging between 34% and 131% across food groups. This suggests that rising relative food costs have led to deterioration of the food security situation in Kenya, and the most severely affected households seem to be those that rely on informal markets and reside in rural areas. To improve food security, targeted income support could be a more effective policy than price support, given the much higher estimated expenditure elasticities.     

THE ELASTICITY OF SUBSTITUTION BETWEEN TIME AND MARKET GOODS: EVIDENCE FROM THE GREAT RECESSION

We document a change in household shopping behavior during the Great Recession. Households purchased more on sale, larger sizes, and generic products and increased coupon usage and shopping at discount stores. We estimate a decline in returns to shopping during the recession. Therefore, the increase in shopping behavior implies a significant decrease in households' opportunity cost of time. Using the estimated cost of time and time use data, we estimate a high elasticity of substitution between market expenditure and time spent on nonmarket work. We find that households smooth a sizable fraction of consumption by varying their time allocation during recessions.     

The price of education and inequality

Constructing a simple model that includes the price of education, this paper shows that the educational expenditure of rich households could prevent poor households from escaping poverty. The paper offers an explanation for persistent inequality.     

Estimating Purchasing Power Parities from Household Expenditure Data Using Complete Demand Systems with Application to Living Standards Comparison: India and Vietnam

This study departs from the previous literature on purchasing power parity (PPP) by proposing a demand system based methodology for calculating the PPP that takes account of consumer preferences and allows for the substitution effect of price changes. The methodology is used to calculate the PPP between the Indian Rupee and the Vietnamese Dong. The study allows for regional variation in preferences and price changes both inside the country and between countries. It proposes and applies a methodology for constructing prices from unit values after adjusting them for quality and demographic effects. The adjusted unit values are used as prices in the demand estimations, and the demand parameter estimates are used to calculate both spatial prices within each country and the PPP between the two countries within a consistent framework. The study illustrates the usefulness of preference consistent methods to calculate the PPP by applying the PPPs to compare living standards between India and Vietnam. The significance of the results follows from the fact that the levels of living comparisons are quite sensitive to the PPP used in converting the Rupee expenditure into Vietnamese Dong. The present results on food PPPs question the relevance of the PPPs from the ICP project in cross‐country welfare comparisons especially in a period of high food inflation.     

Conditional and unconditional food demand elasticities in a dynamic multistage demand system

This paper estimates conditional and unconditional demand elasticities in a three stage analysis of consumer demand for food and non-food items in Greece. A dynamic version of the AIDS model is specified and estimated, and full system misspecification tests applied. Correction formulas for price and expenditure elasticities are used to calculate unconditional elasticities from conditional demand sub-systems. All food items rank as price inelastic. Deviations between the calculated conditional and unconditional price and expenditure elasticities are found to be significant, demonstrating the importance of correcting conditional elasticities before they can be used for policy purposes or welfare analyses.     

Determinants of food consumption in rural Sierra Leone: Application of the quadratic expenditure system to the consumption-leisure component of a household-firm model

This paper reports the application of a quadratic expenditure system with demographic variables to the household consumption-leisure choice component of a household-firm model. A system of seven commodities is estimated: including five foods, non-food and leisure. Appropriate for such a level of disaggregation a demand system is used, the Quadratic Expenditure System, which allows for a flexible relationship between full income and commodity expenditures without sacrificing parsimony in parameters. Demographic data on households are explicitly incorporated into the model allowing for a richer specification than can be achieved by using per capita variables. The data are from a cross-section survey of households in rural Sierra Leone. Price variation exists by region, permitting estimation of a complete demand system. Engel curves are found to be significantly non-linear, with marginal expenditure on rice, the major staple, declining with higher income. Most foods are found to be reasonably price responsive with sizeable own price substitution effects, declining with higher income. Aggregate labor supply is found to be price inelastic.     

Intertemporal elasticity of substitution and risk aversion: are they related empirically?

This article examines the relationship between two types of preference: preference of intertemporal choices and preference towards risk. In the simplest form of the constant relative risk aversion utility function, the intertemporal elasticity of substitution (IES) and risk aversion have an inverse relationship. However, there is no empirical evidence that suggests this inverse relationship holds. We examine the relationship between risk aversion and IES using household consumption data from the Consumer Expenditure Survey during 1996–2010. Multiple risk domains are selected to represent risk preference, and for each domain, we consider some households to be more risk averse than others. We separately estimate IES for the more risk-averse and less risk-averse households. We find that the IES estimates are generally smaller for the more risk-averse households than for the less risk-averse households and that the difference is statistically significant in the majority of the financial domains. This finding supports the inverse relationship between the two parameters, although considerable heterogeneity is found across domains.