Lorenz non-consistent welfare and inequality measurement

Typical welfare and inequality measures are required to be Lorenz consistent which guarantees that inequality decreases and welfare increases as a result of a progressive transfer. We explore the implications for welfare and inequality measurement of substituting the weaker absolute differentials and deprivation quasi-orderings for the Lorenz quasi-ordering. Restricting attention to distributions of equal means, we show that the utilitarian model - the so-called expected utility model in the theory of risk - does not permit one to make a distinction between the views embedded in the differentials, deprivation and Lorenz quasi-orderings. In contrast it is possible within the dual model of M. Yaari (Econometrica 55 (1987), 99–115) to derive the restrictions to be placed on the weighting function which guarantee that the corresponding welfare orderings are consistent with the differentials and deprivation quasi-orderings respectively. Finally we drop the equal mean condition and indicate the implications of our approach for the absolute ethical inequality indices.     

An extended Gini approach to inequality measurement

It is well-known that, when the Lorenz curves do not cross, the ranking of distributions provided by the Gini index is identical to the one implied by the Lorenz criterion. This does not preclude inequality as measured by the Gini index to increase while the Lorenz curves cross. A suitable modification of the Gini coefficient allows the Lorenz quasi-ordering to coincide with the ranking generated by the application of unanimity over the class of extended Gini indices. Recently the Lorenz quasi-ordering and the underlying principle of transfers have come under attack, while new criteria – the differentials, deprivation and satisfaction quasi-orderings – have been proposed for providing unambiguous rankings of distributions. We suggest to weaken the principle of transfers by imposing additional restrictions on the progressive transfers, which take into account the positions on the income scale of the donors and beneficiaries. We identify the subclasses of extended Gini indices that satisfy these weaker versions of the principle of transfers and we show that the application of unanimity among these classes generate rankings of distributions that coincide with those implied by the differentials, deprivation and satisfaction quasi-orderings.      

Comparing degrees of inequality aversion

We propose a straightforward dominance procedure for comparing social welfare orderings (SWOs) with respect to the degree of inequality aversion they express. Three versions of the procedure are considered, each of which uses a different underlying criterion of inequality comparisons: (i) a concept based on the Lorenz quasi-ordering, which we argue to be the ideal version, (ii) a concept based on a minimalist criterion of inequality, and (iii) a concept based on the relative differentials quasi-ordering. It turns out that the traditional Arrow–Pratt approach is equivalent to the latter two concepts for important classes of SWOs, but that it is profoundly inconsistent with the Lorenz-based concept. With respect to the problem of combining extreme inequality aversion and monotonicity, concepts (ii) and (iii) identify as extremely inequality averse a class of SWOs that includes leximin as a special case, whereas the Lorenz-based concept (i) concludes that extreme inequality aversion and monotonicity are incompatible.     

Inequality orderings and unit consistency

The paper examines the implications of the newly proposed unit consistency axiom for partial inequality orderings. We first show that some intermediate Lorenz dominance conditions violate the axiom. We then characterize a class of intermediate Lorenz orderings and demonstrate that the only unit-consistent member is the one related to Krtscha (Models and measurement of welfare and inequality. Springer, Heidelberg, 1994)’s intermediate notion of inequality which has recently been investigated by Zoli (A surplus sharing approach to the measurement of inequality. Discussion paper no. 98/25, University of York, 1998; Logic, game, theory and social choice. Tilburg University Press, Tilburg, 1999) and Yoshida (Soc Choice Welf 24:557–574, 2005). Finally, we provide a general characterization for unit-consistent Lorenz orderings and the Krtscha-type dominance again turns out to be the only one that is intermediate and unit-consistent.     

Utility-gap Dominances and Inequality Orderings

The justification for using Lorenz dominance as an inequality ranking condition has been based on the aggregate social welfare comparison and the Pigou–Dalton principle of transfers. Since both the aggregating aspect of the social welfare function and certain implications of the principle of transfers are debatable, ordering conditions stronger than Lorenz dominance are worth exploring. A particularly interesting direction to pursue is to follow the frequently invoked notion that inequality is the “gap” between the rich and the poor. This paper follows this notion to formally propose a unified utility-gap concept and characterizes several utility-gap based conditions as general stronger-than-Lorenz-dominance ranking criteria. Specifically, we propose utility-gap dominance which requires all pair-wise utility-gaps in one distribution to be uniformly smaller than those of the other distribution. We then explore a conceptually weaker dominance concept – quasi dominance – which imposes conditions only on the gap between each person’s utility and some reference utility point of the distribution. I am grateful to two anonymous referees and Peter Lambert for their very constructive comments and suggestions on an earlier version of the paper. The usual caveat applies.     

The measurement of opportunity inequality: a cardinality-based approach

We consider the problem of ranking distributions of opportunity sets on the basis of equality. First, conditional on a given ranking of individual opportunity sets, we define the notion of an equalizing transformation. Then, assuming that the opportunity sets are ranked according to the cardinality ordering, we formulate the analogues of the notions of the Lorenz partial ordering, equalizing (Dalton) transfers, and inequality averse social welfare functions – concepts which play a central role in the literature on income inequality. Our main result is a cardinality-based analogue of the fundamental theorem of inequality measurement: one distribution Lorenz dominates another if and only if the former can be obtained from the latter by a finite sequence of rank preserving equalizations, and if and only if the former is ranked higher than the latter by all inequality averse social welfare functions. In addition, we characterize the smallest monotonic and transitive extension of our cardinality-based Lorenz inequality ordering. Received: 2 May 1995 / Accepted: 11 October 1996     

Using equivalent income of equivalent adults to rank income distributions

The paper proposes the consistent and rigorous use of equivalence scales for households of different size. Equivalence scales are employed for deriving the income of an equivalent adult representing the household and for weighting the different household types. The proceeding takes into account the possibilities and the needs of different household types at the same time and seems to be adequate if income distributions are to be compared in terms of social welfare or inequality. The approach allows to define and to investigate the usual concepts (Lorenz curve, Lorenz dominance, social welfare function, progressive transfers etc.) for heterogeneous populations. They can be interpreted in an obvious way, and the results, well known for homogeneous populations, can be generalized. Furthermore, some unpleasant and unsatisfactory paradoxa or impossibility results, which can be found in the literature, vanish in the framework considered. Received: 7 March 1997/Accepted: 4 November 1997     

Deprivation,welfare and inequality

We provide a characterization of the generalised satisfaction—in our terminology non-deprivation—quasi-ordering introduced by S.R. Chakravarty (Keio Econ Stud 34:17–32, (1997)) for making welfare comparisons. The non-deprivation quasi-ordering obeys a weaker version of the principle of transfers: welfare improves only for specific combinations of progressive transfers, which impose that the same amount be taken from richer individuals and allocated to one arbitrary poorer individual. We identify the extended Gini social welfare functions that are consistent with this principle and we show that the unanimity of value judgements among this class is identical to the ranking of distributions implied by the non-deprivation quasi-ordering. We extend the approach to the measurement of inequality by considering the corresponding relative and absolute ethical inequality indices. This is a shortened version of Magdalou and Moyes (2008), which contains the details of the proofs as well as an empirical illustration.     

Size and distribution trade-offs for the leximin ordering

A relative invariant and an absolute invariant inequality ordering satisfying extreme bottom-sensitivity, are proposed. It is shown that the leximin social welfare ordering can be expressed in terms of a ranking of distributions on the sole basis of their size, measured by the mean, and the degree of inequality, measured according to these inequality concepts. Leximin thus exhibits extreme bottom-sensitivity. This property does not withstand that leximin prefers a larger size of the cake at the cost of higher inequality in a number of cases. These trade-offs between size and equality are characterised in terms of degrees of dominance of the lower parts of the ordinary and absolute Lorenz curves that are accepted by leximin for a given increase in the mean.     

Robust inequality comparisons

This paper is concerned with the problem of ranking Lorenz curves in situations where the Lorenz curves intersect and no unambiguous ranking can be attained without introducing weaker ranking criteria than first-degree Lorenz dominance. To deal with such situations, Aaberge (Soc Choice Welf 33:235–259, 2009) introduced two alternative sequences of nested dominance criteria for Lorenz curves, which proved to characterize two separate systems of nested subfamilies of inequality measures. This paper uses the obtained characterization results to arrange the members of two different generalized Gini families of inequality measures into subfamilies according to their relationship to Lorenz dominance of various degrees. Since the various criteria of higher degree Lorenz dominance provide convenient computational methods, these results can be used to identify the largest subfamily of the generalized Gini families, and thus the least restrictive social preferences, required to reach unambiguous ranking of a set of Lorenz curves. We further show that the weight-functions of the members of the generalized Gini families offer intuitive interpretations of higher degree Lorenz dominance, which generally has been viewed as difficult to interpret because they involve assumptions about third and higher derivatives. To demonstrate the usefulness of these methods for empirical applications, we examine the time trend in income and earnings inequality of Norwegian males during the period 1967–2005.     

Elitism and stochastic dominance

Stochastic dominance has been typically used with a special emphasis on risk and inequality reduction something captured by the concavity of the utility function in the expected utility model. We claim that the applicability of the stochastic dominance approach goes far beyond risk and inequality measurement provided suitable adaptations be made. We apply in this article the stochastic dominance approach to the measurement of elitism which may be considered the opposite of egalitarianism. While the usual stochastic dominance quasi-orderings attach more value to more equal and more efficient distributions, our criteria ensure that, the more unequal and the more efficient the distribution, the higher it is ranked. Two instances are provided by (i) comparisons of scientific performance across institutions like universities or departments, and (ii) comparisons of affluence as opposed to poverty between countries.     

Ethical inequality measures and the redistribution of income when needs differ

The paper considers nested social welfare functions and ethical inequality measures when households may differ in needs. Several principles of transfers between different household types are introduced and systematically examined. Their implications for the form of welfare functions and inequality measures are derived. The corresponding classes are completely described.      

Gini’s nuclear family

The purpose of this paper is to justify the use of the Gini coefficient and two close relatives for summarizing the basic information of inequality in distributions of income. To this end we employ a specific transformation of the Lorenz curve, the scaled conditional mean curve, rather than the Lorenz curve as the basic formal representation of inequality in distributions of income. The scaled conditional mean curve is shown to possess several attractive properties as an alternative interpretation of the information content of the Lorenz curve and furthermore proves to yield essential information on polarization in the population. The paper also provides asymptotic distribution results for the empirical scaled conditional mean curve and the related family of empirical measures of inequality.      

Ranking intersecting Lorenz curves

This paper is concerned with the problem of ranking Lorenz curves in situations where the Lorenz curves intersect and no unambiguous ranking can be attained without introducing weaker ranking criteria than first-degree Lorenz dominance. To deal with such situations two alternative sequences of nested dominance criteria between Lorenz curves are introduced. At the limit the systems of dominance criteria appear to depend solely on the income share of either the worst-off or the best-off income recipient. This result suggests two alternative strategies for increasing the number of Lorenz curves that can be strictly ordered; one that places more emphasis on changes that occur in the lower part of the income distribution and the other that places more emphasis on changes that occur in the upper part of the income distribution. Both strategies turn out to depart from the Gini coefficient; one requires higher degree of downside and the other higher degree of upside inequality aversion than what is exhibited by the Gini coefficient. Furthermore, it is demonstrated that the sequences of dominance criteria characterize two separate systems of nested subfamilies of inequality measures and thus provide a method for identifying the least restrictive social preferences required to reach an unambiguous ranking of a given set of Lorenz curves. Moreover, it is demonstrated that the introduction of successively more general transfer principles than the Pigou–Dalton principle of transfers forms a helpful basis for judging the normative significance of higher degrees of Lorenz dominance. The dominance results for Lorenz curves do also apply to generalized Lorenz curves and thus provide convenient characterizations of the corresponding social welfare orderings.     

Social welfare rankings of income distributions A new parametric concept of intermediate inequality

This paper installs a new concept of intermediate inequality, which we refer to as η-inequality equivalence, in the notable form of equivalence of the Lorenz partial ordering and social welfare dominance. The η-inequality equivalence is a parameterized generalization of Krtscha’s (1994) non-linear compromise between the relative and absolute inequality views. For each η ∈ [0,1], we place a class of social evaluation functions satisfying the S-concavity as well as the property that an increase in incomes while leaving η-inequality intact raises welfare. We prove that one income distribution dominates another for all social evaluation functions in iff the former has a higher mean and a higher η-Lorenz curve. We prove also that the class is strictly increasing in the sense of inclusion as η decreases.I am grateful to Kiyoshi Kuga for his helpful comments and suggestions. I am also grateful to an anonymous referee and an associate editor for many valuable comments and suggestions that have much improved the paper. A previous version of this paper was presented at the annual meeting of the Japanese Economic Association, October 7, 2001, Tokyo, Japan. I wish to thank Takashi Toyoda for his helpful comments and suggestions at the meeting. This research was supported in part by the Ministry of Education, Culture, Sports, Science and Technology in Japan (Grant-in-aid for Scientific Research No.12630032).     

On the welfare loss caused by inequality of opportunity

Based on the ethical principle of equality of opportunity, this paper presents a measure of the welfare loss that is caused by an unfair distribution of a particular outcome (income, health, education, etc). The key idea is that a fair society should produce outcomes that depend on individuals’ effort and not on their external circumstances such as gender, socioeconomic background, etc. We propose measuring inequality of opportunity as the welfare loss attributed to the outcome differences among individuals who exert a similar level of effort. Our results are in line with those aspects of fairness literature that give priority to the ex post compensation approach to equality of opportunity. Finally, we present an empirical application for the measurement of the welfare loss in the income distribution in Europe. We have observed a high degree of heterogeneity among European countries. The welfare loss due to inequality of opportunity ranges in those, from basically zero to almost one fifth of their potential welfare.     

A deprivation-based axiomatic characterization of the absolute Bonferroni index of inequality

We investigate several properties of the Bonferroni inequality index, including its welfare theoretic interpretation. We also interpret and characterize the absolute Bonferroni index as the average of subgroup average depression indices, where to each income we associate a subgroup containing all persons whose incomes are not higher than this income. An aggregate depression index for a subgroup has been derived axiomatically as the sum of gaps between the subgroup highest income and all incomes not higher than that.      

Spousal resources and relationship quality in eight European countries

ABSTRACT

We relate relationship satisfaction and thoughts about leaving a romantic relationship to a couple’s relative and absolute resources and check for context-dependency of those associations. Our theoretical point of departure is that the more resources women have compared to their spouses, the higher their intra-household bargaining power to negotiate themselves out of unpleasant tasks, particularly in gender-egalitarian and very income equal and unequal societies. In traditional societies (which score low on the Gender Empowerment Measure (GEM)), the inflexible role of men within the household presumably prevents women from bargaining a better position, which in turn negatively affects relationship quality. Income equality (low GINI coefficient) may be a prerequisite for women’s bargaining position, where more inequality (mid-GINI) may be detrimental for it. Nevertheless, extreme income inequality (high GINI) may again be favorable for women’s relationship power. Using country fixed effects models on data from the Generations and Gender Surveys (GGS), we compare men and women who are in a couple (formed after 1995) for eight European countries. We find that absolute resources matter more than relative resources, at least for relationship satisfaction: Higher educated couples are more satisfied with their relationships, which could suggest lower stress levels in those couples (in more traditional contexts). Second, we observe GINI context-dependency of the association between relative education and relationship satisfaction for women and relative education and exit thoughts for men, although opposite to what we expected. Perhaps reference group theory or gender display theory can explain these unexpected results. Finally, we find that women have more break-up plans in societies with a lower score on GEM. This last result is consistent with the notion that bargaining only works in egalitarian contexts.     

Ranking Income Distributions According to Equality of Opportunity

According to the opportunity egalitarian ethics, economic inequalities due to factors beyond the individual responsibility are inequitable and to be compensated by society, whereas inequalities due to personal responsibility are equitable and not to be compensated. In this paper we derive welfare and inequality criteria that respect this principle of justice. We characterize axiomatically classes of opportunity egalitarian social evaluation functions. Then, by requiring unanimous agreement among such classes, we provide simple distributional conditions to rank income distributions. These criteria extend the Lorenz and generalized Lorenz partial orderings, commonly used in the unidimensional case of income distributions, to the current context of equality of opportunity.     

Punishment,inequality, and welfare: a public good experiment

This paper reports the results of an experiment that investigates the two-sided relationship between punishment and welfare. First, it contributes to the literature on the behavioral determinants of punishment by examining the role of relative income and income comparisons as a determinant of punishment in a two-stage public good game when inequality arises endogenously from the subjects’ behavior. Second, this paper investigates the impact of punishment on both absolute and relative incomes. We compare three treatments of our game. The Unequal Cost treatment replicates Fehr and Gächter (2000)’s experiment under a stranger matching protocol. The Equal Cost treatment is identical to the previous one except that the ratio between the cost of one punishment point to the punisher and its cost to the target equals one. The third treatment is similar to the second one except that a partner matching protocol is implemented in order to isolate strategic motives for punishment. Our results indicate that subjects punish even when they cannot alter the current distribution of payoffs. We also find that in all treatments, the intensity of punishment increases in the level of inter-individual inequality. Finally, despite its cost, punishment progressively improves welfare in association with a decrease in the aggregate level of inequality over time.