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.     

City size and household food consumption: demand elasticities in Spain

Are food price elasticities different across city sizes? The aim of this article is to estimate expenditure and own-price elasticities for 10 aggregated food product groups using the Spanish Household Budget Survey for the year 2010. These products are the ones for which the survey provides information regarding prices and quantities, thus allowing the application of an Almost Ideal Demand System (AIDS) model with censored data. The estimation procedure allows not only comparisons to be made among households with different levels of income, but also the contribution of residence characteristics to variations in demand. The results confirm that the size of the city in which the household resides has a similar significant and relevant effect on consumption patterns as family income level. This is especially clear with own-price elasticities. In Spain, large central cities show a greater response to price changes than smaller cities or rural peripheral areas.     

Carbon mitigation costs for the commercial building sector: Discrete–continuous choice analysis of multifuel energy demand

We estimate a carbon mitigation cost curve for the U.S. commercial sector based on econometric estimation of the responsiveness of fuel demand and equipment choices to energy price changes. The model econometrically estimates fuel demand conditional on fuel choice, which is characterized by a multinomial logit model. Separate estimation of end uses (e.g., heating, cooking) using the U.S. Commercial Buildings Energy Consumption Survey allows for exceptionally detailed estimation of price responsiveness disaggregated by end use and fuel type. We then construct aggregate long-run elasticities, by fuel type, through a series of simulations; own-price elasticities range from −0.9 for district heat services to −2.9 for fuel oil. The simulations form the basis of a marginal cost curve for carbon mitigation, which suggests that a price of $20 per ton of carbon would result in an 8% reduction in commercial carbon emissions, and a price of $100 per ton would result in a 28% reduction.     

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.     

Consumption patterns in Sri Lanka: a decomposition analysis

Knowing consumer reaction to changes in prices and income is important in formulating microeconomic policies, such as public utility prices and commodity taxation. This paper analyses the consumption patterns of consumer goods grouped into eight broad commodities in Sri Lanka during the period 1975–2016, using a system-wide framework. The analysis indicates that Sri Lankan consumers allocate more than half of their income to food and nearly four fifths of their income to food, housing, and transport combined. The estimated income and own-price elasticities reveal that food, housing, medical care, and transport are necessities; clothing, durables and recreation are luxuries; and demand for all commodities is price inelastic except for recreation. To investigate the consumption growth pattern, we decomposed the growth in consumption and change in budget shares of the eight commodities into income, relative price, and change in taste. We also simulated per capita consumption expenditure of the eight commodities under various policy scenarios and found that income growth has played a significant role in Sri Lankan consumption patterns.     

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.     

Elasticity estimates of farmed salmon demand in Spain and Italy

In this paper, estimates of the elasticities that characterize the structure of demand for farmed salmon in Spain and Italy are reported. The demand models are specified using a Box-Cox transformation of the variables and a Hausman test is used to determine price endogeneity in the demand equations. The results show short-run unitary own-price elasticity of demand for farmed salmon in both markets, but long run estimates show significant elastic price response. Short run substitution of salmon for other fish species is not observed and, for both Spain and Italy, farmed salmon is characterized as a luxury good. Interestingly, we show that our a priori expectations about own-price elasticities being lower in smaller market areas is confirmed. Finally, the results obtained are compared to other recent results reported in the salmon demand literature.     

The demand for residential electricity: new evidence on time-varying elasticities

This study employs a generalized functional form to examine demand for residential electiricity. The appropriatenes of the conventional double-log and linear forms are tested. Time-varying elasicities are estimated. Major findings are summarized as follows:(1) the double-log and linear forms can be rejected at the 0.05 and 0.01 levels, respectively; (2) long-run own-price elasticities declined in absolute value consistently from 2.13 to 1.19 during the period 1950–87; (3) long-run income elasticities also decreased from 1.29 to 0.97 during the same period; and (4) long-run corss-Price elasticities with respect to the price of natural gas dropped form 0.40 to 0.29. These results may be heplful to decision makers in determining the change in total revenues owning to the change in prices, pricing strategies, the effectiveness of energy conservation programmes, the effect of rising real income on the demand for residential electricity and future demand.     

Demand elasticities for international message telephone service

Using a point-to-point model of toll demand, this paper provides estimates of own-price demand elasticities for international message telephone service. The study improves on previous studies by using more recent data and endogenizing price. Consistent with earlier studies, the demand for IMTS is found to be price inelastic, about??0.28 on average, in the short-run and near unitary elastic,??1.04 on average, in the long run. Both the level and the elasticity of demand are found to be positively related to the size of the telephone network. The own-price elasticity of demand for a select group of countries is provided.     

Cross-section estimation of US demand for alcoholic beverage

A flexible limited dependent variable model is used to examine US demand for alcoholic beverage. Parameterization and distributional assumptions of the double hurdle model (Cragg, 1971) and tobit model (Tobin, 1958) are rejected. Findings suggest that price, income, household composition and other characteristics have significant effects on alcohol consumption. Income and own-price elasticities are significant but relatively small.     

British tourism demand elasticities in Mediterranean countries

We use the almost ideal demand system (AIDS) model developed by Deaton and Muellbauer (1980) to estimate tourism demand elasticities for a number of Mediterranean countries (Cyprus, Greece, Italy, Malta, Portugal, Spain and Turkey) in relation to tourists originating from the United Kingdom during the period 1963 to 2009. Using the restrictions imposed by theory, we find that the model is able to explain developments in market shares reasonably well, despite the large and at times sudden changes in market shares over the sample period. Our share estimates indicate that while Spain and Portugal managed to keep a stable market share over time, Malta and especially Italy lost market share to Cyprus, Greece and Turkey. Overall, we observe that Italy and Spain have the lowest own-price elasticities, whereas Greece, Portugal, Spain and Turkey are expenditure inelastic holiday destinations. We also improve over the traditional treatment of the AIDS model in the literature by studying the stability of the estimated elasticities over time using recursive estimates. The results indicate that some elasticities are indeed time varying and highlight the potential pitfalls of assuming fixed and stable elasticities over a long period, as is customary in the tourism literature.     

Effects of Changes in Household Size,Consumer Taste & Preferences on Demand Pattern in India

Current research in applied demand analysis has been addressing the twin issues of degree of non-linearity or curvature of the Engel curves and the ability to capture price effects appropriately by the demand system. Further, in addition to income and prices, the role of demographic variables like household size, composition and dynamic aspects like consumer taste & preferences are also being ’ emphasized in recent literature. Continuous efforts are being made to modify the existing models and propose new ones to incorporate the above developments. The purpose of this study is to re-examine the usefulness of the popular linear expenditure system vis-à-vis the two other flexible models viz. Nasse expenditure system, a generalization of the linear expenditure system itself, and the almost ideal demand system in the above context for India.The empirical results indicate wide variation in marginal budget shares and demand elasticities across income groups, rural-urban sectors and alternative models. The household size and consumer taste & preferences are found to be statistically significant. The results confirm the earlier findings that there are significant changes in consumer tastes away from cereals and pulses in favor of other food and nonfood commodities. The results also show that flexible models, which are theoretically superior, gave unacceptable positive price responses for some commodities and violated second order conditions of utility maximization. It is found that some ad-hoc separability restrictions are needed, thereby limiting the flexibility of the model, to get negative own-price responses in these models. But, second order conditions are still violated. The tests of nested hypotheses also confirm the need for inclusion of household size, consumer taste, income group and rural-urban dummies along with their interaction variables in the demand system.

     

The influence of recession and income strata on consumer demand for protein sources

Though meat products are considered the primary sources of protein in the U.S., people consume a variety of protein sources including meat, fish, eggs, dairy products and beans. This study expands the typical meat demand study by including alternate protein sources. We implement state-space modelling and Bai-Perron tests to examine structural change in U.S. expenditure patterns on protein sources across pre- and post-recessionary periods. Results are integrated into a Time-Varying Almost Ideal Demand System (AIDS) including beef, pork, poultry, fish and seafood, eggs, dairy products, dried beans, and an ‘other meat’ composite. Expenditure elasticities generally become relatively more elastic post-recession for protein sources across all income quintiles, with the largest changes in beef and pork. The lowest income group exhibits the least change in own-price and in expenditure elasticities, likely an indication of already limited flexibility.     

Measuring the effectiveness of non-price export promotion using a supply-side approach

In this paper we assess the effectiveness of the Market Promotion Program (MPP) in increasing U.S. exports and benefitting U.S. agricultural producers and food processors. Export shipments are linked to producer welfare using Kohli's (1978) profit maximization (GNP function) approach to modeling international trade. Using estimated profit functions in conjunction with a synthetic export demand function for processed agricultural products, we compute changes in farm and food processing sector profits that result from alternative own-price and advertising elasticities of export demand with and without the MPP subsidy. This approach allows us to investigate aggregate welfare effects of nonprice promotion without requiring the difficult task of estimating the export demand effects of market promotion activities for numerous commodities and importing countries. First version received: April 1999/Final version received: June 2000     

Demand for international telephone traffic in Spain: An econometric study using provincial panel data

In this study we model the demand for outgoing international telephone traffic in Spain. We make use of a standard theoretical framework that incorporates the special characteristics of this type of telephone service. Consequently, equations for real expenditure per line and for the number of international calls per line are estimated.We use annual data for the 50 Spanish provinces for the period 1985–1989, and employ appropriate panel data techniques. The selected equations (one for expenditure per line in international traffic and another for the number of international calls per line) pass a battery of diagnostics. We conclude that this type of traffic, whether measured by expenditure per line or by the number of international calls per line, presents both high income and price elasticities. Moreover we find that price and income affect both the number of calls and their average duration.Likewise, we find a significant increase in social welfare when a tariff rebalancing that maintains the profit of the operating company is carried out.     

An analysis of the demand for housing attributes

This paper uses a two-step approach to estimate a system of structural demand equations for housing attributes. Estimation of a hedonic price regression, in the first step, yields implicit prices for housing attributes for the Toronto Metropolitan area in 1978, which are then used to estimate the expenditure share equations derived from the indirect translog utility function. Empirical results indicate that the composite housing attributes (used in the second stage model) are own-price elastic, while an examination of cross price relationships reveals that these attributes are reasonably substitutable.     

Household demand for fats and oils: two-step estimation of a censored demand system

A censored system of household fat and oil demand equations is estimated with a two-step procedure, using cross-sectional data from the 1987–1988 US Nationwide Food Consumption Survey. Own price and total expenditure elasticities are close to unity and there is no evidence of gross substitutability. Compensated elasticities suggest net substitution among the products considered.     

Economic determinants of global mobile telephony growth

This study examines the substitution effect between fixed-line and mobile telephony while controlling for the consumption externality associated with telephone networks. A dynamic demand model is estimated using a global telecommunications panel dataset comprised of 56 countries from 1995–2000. Estimation results show the presence of a substantial substitution effect. Additionally income and own-price elasticities are reported. Analysis of impulse responses for price, income and network size indicate substantial mobile telephone growth is yet to be realised. However, price ceilings imposed in the fixed-line network can retard the growth of the mobile network.     

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.     

The US retail demand for fish products: an application of the almost ideal demand system

The main objective is to address the limitations of past US fish demand research through the development of a variation of the almost ideal demand system model for disaggregate fish products at the retail level. Price and expenditure elasticities, as well as elasticities of substitution between fish products and other protein commodities, determined from this work may be used in the context of fisheries management and market development and promotion. Results indicate that with the exception of shellfish, demand for the various fish products is relatively inelastic. Cross-price elasticities are generally moderate while expenditure elasticities are large and positive for fresh fish and shellfish. Demographic effects, especially geographical division, season, race, occupation, age–sex household composition, and price–income interaction, as a proxy for quality, are highly significant variables.