THE SENSITIVITY OF INCOME INEQUALITY TO CHOICE OF EQUIVALENCE SCALES

To account for the fact that a household's needs depend on its size and composition most studies on income inequality adjust the observed household incomes by equivalence scales. However, since the rationale for choosing a specific scale is rather vague the importance of testing the sensitivity of income inequality estimates to choice of equivalence scales has long been acknowledged. The sensitivity studies in the literature are restricted to equivalence scales that do not depend on the income level of the reference household which means that the effect of a rise in the household size on the scale rate does not depend on whether the household is poor or rich. By using Norwegian micro-data it is shown that the introduction of an income-dependent scale produces results that are in conflict with the widespread view of robustness of results to choice of equivalence scales.     

Equivalence Scales in an Intertemporal Setting with an Application to the Former West Germany

Equivalence scales provide answers to questions like how much a household with two children needs to spend compared to a couple to attain the same welfare level. These are important questions for child allowances, social benefits and to assess the cost of children over the life-cycle for example. We discuss equivalence scales in an intertemporal setting with uncertainty. To estimate equivalence scales we use a panel from German households (GSOEP) containing subjective data on satisfaction with life and satisfaction with income to represent the welfare level. Because satisfaction is measured on a discrete scale we use limited dependent variable models for panel data in estimation. Using satisfaction with life data we find that larger households do not need any additional income to be as satisfied as a couple. Using satisfaction with income, however, yields equivalence scales that increase with household size.     

EQUIVALENCE SCALES, WELL-BEING, INEQUALITY, AND POVERTY: SENSITIVITY ESTIMATES ACROSS TEN COUNTRIES USING THE LUXEMBOURG INCOME STUDY (LIS) DATABASE

The Luxembourg Income Study (LIS) database on which this article is based offers researchers exciting new possibilities for international comparisons based on household income microdata. Among the choices the LIS microdata allows a researcher, e.g. income definition, income accounting unit, etc., is the choice of family equivalence scale, a method for estimating economic well-being by adjusting income for measurable differences in need.
The range of potential equivalence scales that can and are being used in the ten LIS countries and elsewhere to adjust incomes for size and related differences in need span a wide spectrum. The purpose of this paper is to review the available equivalence scales and to test the sensitivity of various income inequality and poverty measures to choice of equivalence scale using the LIS database. The results of our analysis indicate that choice of equivalence scale can sometimes systematically affect absolute and relative levels of poverty; and inequality and therefore rankings of countries (or population subgroups within countries). Because of these sensitivities, one must carefully consider summary statements and policy implications derived from cross-national comparisons of poverty and/or inequality.     

NONCASH INCOME, EQUIVALENCE SCALES, AND THE MEASUREMENT OF ECONOMIC WELL-BEING

Little attention has been paid to the importance of consistency between the specifications of the income and the equivalence scales used in measuring economic well-being when noncash income is included in the definition of income. This article finds that inconsistency between the income and needs sides of a comparison can be important when some types of noncash income are included. An upward bias in the measured economic status of the aged when Medicare is included in income and an ordinary equivalence scale is used is presented as an example of the important effects of this consistency problem.     

Statics and Dynamics of Income Distribution: An Introductory Survey

Abstract
This article discusses some of the issues involved in making comparisons of income distributions using cross-sectional data and in examining the dynamics of income distribution using longitudinal data. Any study of income distribution must consider the unit of analysis, the time period and the measure of income, and these are the focus of the article. Section 2, on annual incomes, begins with problems of intra-household income sharing and the measure of income used, including household production. Comparisons among households of different size are discussed, involving the choice of equivalence scales, the use of decomposition analysis and more general dominance conditions. The role of value judgments in the use of equivalence scales is stressed. Section 3 is concerned with dynamic aspects of income distribution. It discusses methods of constructing synthetic cohorts for use in simulation exercises, the varieties of longitudinal data available, sample attrition and the unit of analysis. An appendix provides further references to the literature and data sources .     

USING FUNCTIONINGS TO ESTIMATE EQUIVALENCE SCALES

Equivalence scales are used to enable welfare comparisons across heterogeneous households. In this paper, we propose to use the achievement of a certain level of functioning as the identifying assumption for the derivation of equivalence scales. This will allow us not only to deal with welfare comparisons between households of different size and composition, but will also enable us to incorporate other characteristics (such as location and employment status) in the creation of equivalence scales for welfare comparisons. The paper applies this approach to create equivalence scales for the functioning “shelter” using Belgian and Italian data. The analysis shows that the income differences associated with different characteristics only play a small role in explaining differences in functionings. An important policy message is therefore that compensating people for functioning shortfalls in monetary terms may not be sensible.     

RELATIVE INEQUALITY AND POVERTY IN GERMANY AND THE UNITED STATES USING ALTERNATIVE EQUIVALENCE SCALES

We use data from the Luxembourg Income Study to show the sensitivity of measures of relative economic well-being of persons in the U.S. and Germany using official equivalence scales and consumption-based country-specific equivalence scales developed for the two countries. Overall inequality and poverty levels are found not to be sensitive to the equivalence scale used. However, the official German equivalence scale yields quite different results from the others with respect to the relative income and poverty levels of vulnerable groups within the population, especially older single people.     

Engel Scales for Australia, the Philippines and Thailand: A Comparative Analysis

The purpose of this study is to explore the question of how similar or how different are equivalence scales of selected countries in the Asia-Pacific region. In particular, the article investigates whether equivalence scales for Australia, the Philippines and Thailand are comparable. That the Philippines and Thailand are two countries which are strikingly similar in their levels of socioeconomic development suggests the possibility that the relative income needs of households of different sizes in these countries are similar. In contrast, Australia is seen as an industrialised nation unlikely to have scales similar to the two other countries. The comparability problem is addressed via the widely used Engel estimation methodology applied to similarly selected samples and a common model specification. It is found that the level of agreement between the country-specific scales is highly dependent on what ‘basket of necessities’ is used as an indicator of welfare. An interesting outcome that may well be of useful empirical significance is that with necessities defined to include food, clothing, and housing (and possibly, medical care as well), the equivalence scales for the Philippines, Thailand and Australia are more or less invariant; no such regularity exists if the definition of necessities is confined to food alone.     

Can PIGLOG preferences identify equivalence scales?

This paper clarifies the conditions under which PIGLOG and extended PIGLOG preferences can identify household equivalence scales. The results are of interest to practitioners who have to elect preferences suitable for welfare analysis. It also shows that independent of the base utility equivalence scales are the same whether the budget shares of the demand systems are linear or quadratic in log income. (JEL: D11, D13) The author is grateful to an anonymous referee for several helpful suggestions.     

EQUIVALENCE SCALE SENSITIVITY OF POVERTY STATISTICS FOR THE MEMBER STATES OF THE EUROPEAN COMMUNITY

Using microdata from Household Budget Surveys of the Member States of the European Community, this paper examines the sensitivity of poverty statistics with respect to the choice of the equivalence scale. The results show that the ranking of the countries with respect to the overall poverty incidence is hardly affected when different equivalence scales are used. However, the composition of the poor population shows considerable changes when e.g. subjective equivalence scales are used instead of the OECD equivalence scale. The poverty incidence among specific household groups, such as single elderly and households with children, is particularly sensitive to the choice of the equivalence scale.     

Semi-parametric models for satisfaction with income

An overview is presented of some parametric and semi-parametric models, estimators, and specification tests that can be used to analyze ordered response variables. In particular, limited dependent variable models that generalize ordered probit are compared to regression models that generalize the linear model. These techniques are then applied to analyze how self-reported satisfaction with household income relates to household income, family composition, and other background variables. Data are drawn from the 1998 wave of the German Socio-Economic Panel. The results are used to estimate equivalence scales and the cost of children. We find that the standard ordered probit model is rejected, while some semi-parametric specifications survive specification tests against nonparametric alternatives. The estimated equivalence scales, however, are often similar for the parametric and semi-parametric specifications.JEL Classification: C14, C35, D12Correspondence to: Charles BellemareWe are grateful to an anonymous referee and to participants of a CeMMAP/ESG workshop at University College London and seminars at CentER (Tilburg University) and Humboldt University Berlin for useful comments.     

Estimating inequality in the distribution of welfare using demand models

In this paper two demand models with general household equivalence scales (GES) are estimated. These GES are identifiable, since they have the independence of base utility (IB) or equivalence scales exactness (ESE) property. Estimates of household characteristics adjusted income can then be calculated relative to a specific household type. This “individual equivalent income (IEI) is then used to calculate measures of inequality in the distribution of welfare. As more than one model is estimated, the sensitivity of these estimates to model specification changes can be considered. Comparisons are also made to estimates of inequality based on household income. It is found that absolute inequality is sensitive to model specification, but relative inequality is not. This is true using indices of inequality of the Atkinson (1970), Kolm (1976a,b) and Sen (1973) type, or more general measures of inequality based on estimates of Lorenz curve decile ordinates, constructed using methods introduced by Beach and Davidson (1983). Thus, if absolute measures of inequality are required, these results suggest some further research is required to determine a class of models which is less sensitive to model specification error. However, if only relative measures of inequality are needed, then estimates of inequality appear to be very robust to the choice of model specification.     

THE ESTIMATION OF PENSIONER EQUIVALENCE SCALES USING SUBJECTIVE DATA

This paper uses panel data on pensioners' subjective evaluations of their financial positions to construct equivalence scales for pensioners. A pensioner couple is estimated to require an income 44 percent higher than a comparable single pensioner to reach the same standard of living. This is significantly less than the equivalence scale value implied by the ratio of state pension rates, the McClements equivalence scale value, and the scale value derived from Engel curve estimation for food expenditure using the same data source. The estimated equivalence scale value is robust to variations in the definition of the pensioner sample, the measurement of income, and the econometric model used.     

Reference Income Effects in the Determination of Equivalence Scales Using Income Satisfaction Data

We estimate household equivalence scales, i.e. the needs of additional adults and children relative to a single adult, using income satisfaction data from the German Socio‐Economic Panel. We extend previous studies applying this approach by taking reference income into account. This allows separating needs‐based from reference effects in the determination of income satisfaction. We show that this adjustment helps to overcome a bias causing an overestimation of adults’ and an underestimation of children’s needs‐based equivalence weights. Our results indicate that controlling for income comparisons substantially increases children’s equivalence weight relative to that of adults.     

THE ESTIMATION OF PENSIONER EQUIVALENCE SCALES USING SUBJECTIVE DATA

This paper uses panel data on pensioners' subjective evaluations of their financial positions to construct equivalence scales for pensioners. A pensioner couple is estimated to require an income 44 percent higher than a comparable single pensioner to reach the same standard of living. This is significantly less than the equivalence scale value implied by the ratio of state pension rates, the McClements equivalence scale value, and the scale value derived from Engel curve estimation for food expenditure using the same data source. The estimated equivalence scale value is robust to variations in the definition of the pensioner sample, the measurement of income, and the econometric model used.     

A new approach to the construction of family equivalence scales

The question of the money compensation which should be given to families of different sizes in order that they enjoy equal welfare levels is considered. By comparison of individual welfare functions, estimated for 3,000 individuals in the Netherlands, family welfare equivalence scales are derived. The obtained equivalence scale depends on family size and the ages of the family members. There are considerable ‘economies of scale’. The method employed may be used to derive money compensations for other situational differences. Evidence was found that people adapt their needs to situational changes. That effect was quantitatively assessed. Results are obtained and compared for various social subgroups.     

Bounding Lifetime Income Using A Cross Section Of Data

Measures of income inequality based on current income are well known to overstate lifetime income inequality for two reasons: intracohort mobility and the shape of the age-earnings profile. Utilizing the concept of age equivalence scales along with varying assumptions concerning the extent of intracohort mobility, the method presented bounds lifetime income inequality using only cross-sectional data from the CPS, 1967–86. As a result, we are able to analyze changes in lifetime inequality over this period.     

A SPECIFICATION SEPARATING FAMILY SIZE AND INDIVIDUAL AGE EFFECTS ON SUBJECTIVE EQUIVALENCE SCALES: A NOTE

This paper analyses the Kapteyn and Van Praag method of estimating equivalence scales with respect to the way family size and age composition are incorporated into the scales according to rank and age of each family member. It becomes evident that the Kapteyn/Van Praag procedure fails to distinguish between household size and individual age effects with the result that personal weights can not be used for recomposition of household types other than wife and husband families, nor can they be interpreted as showing real age dependence of personal income equivalence. For these reasons another specification of the general approach, separating both effects, is outlined. This specification distinguishes between several consumption classes within each household. Within each class, economies of scale are attached to similar individuals while differences in individual need are obtained by comparing individuals with the same rank in the different classes.     

Household Equivalence Scales: New Australian Estimates from the 1984 Household Expenditure Survey*

Equivalence scales are measures of the relative incomes required by households of different size and composition to attain a similar standard of living, and are used in analysis of consumer expenditure patterns as well as in judging the appropriateness of the structure of income maintenance payments. The paper reviews equivalence scales previously derived for Australia and presents a range of new estimates based on the 1984 Household Expenditure Survey.     

The distributional impact of public services when needs differ

Despite a broad consensus on the need to take into account the value of public services in distributional analysis, there is little reliable evidence on how inclusion of such non-cash income actually affects poverty and inequality estimates. In particular, the equivalence scales applied to cash income are not necessarily appropriate when including non-cash income, because the receipt of public services is likely to be associated with particular needs. In this paper, we propose a theory-based framework designed to provide a coherent evaluation of the distributional impact of local public services. The valuation of public services, identification of target groups, allocation of expenditures to target groups, and adjustment for differences in needs are derived from a model of local government spending behaviour. Using Norwegian data from municipal accounts and administrative registers we find that the inclusion of non-cash income reduces income inequality by about 15% and poverty rates by almost one-third. However, adjusting for differences in needs for public services across population subgroups offsets about half the inequality reduction and some of the poverty decrease.