On the Measurement of Long-Term Income Inequality and Income Mobility

This paper proposes a two-step aggregation method for measuring long-term income inequality and income mobility, where mobility is defined as an equalizer of long-term income. The first step consists of aggregating the income stream of each individual into a measure of permanent income, which accounts for the costs associated with income fluctuations and allows for credit market imperfections. The second step aggregates permanent incomes across individuals into measures of social welfare, inequality and mobility. To this end, we employ an axiomatic approach to justify the introduction of a generalized family of rank-dependent measures of inequality, where the distributional weights, as opposed to the Mehran-Yaari family, depend on income shares as well as on population shares. Moreover, a subfamily is shown to be associated with social welfare functions that have intuitively appealing interpretations. Further, the generalized family of inequality measures provides new interpretations of the Gini-coefficient.income inequality, income mobility, social welfare, Gini coefficient, permanent income, credit market, annuity

Money for Nothing? Universal Child Care and Maternal Employment

The strong correlation between child care and maternal employment rates has led previous research to conclude that affordable and readily available child care is a driving force both of cross-country differences in maternal employment and of its rapid growth over the last decades. We analyze the introduction of subsidized, universally accessible child care in Norway. Our precise and robust difference-in-differences estimates reveal that there is little, if any, causal effect of child care on maternal employment, despite a strong correlation. Instead of increasing mothers’ labor supply, the new subsidized child care mostly crowds out informal child care arrangements, suggesting a significant net cost of the child care subsidies.universal child care, female labor force participation

Are Lone Mothers Responsive to Policy Changes? Evidence from a Workfare Reform in a Generous Welfare State

There is a heated debate in many European countries about a move towards a welfare system that increases the incentives for lone mothers to move off welfare and into work. We analyze the consequences of a major Norwegian workfare reform of the generous welfare system for lone mothers. Our difference-in-differences estimates show that the policy changes were successful in improving labor market attachment and increasing disposable income of new lone mothers. By contrast, the reform led to a substantial decrease in disposable income and a significant increase in poverty among persistent lone mothers, because a sizeable group was unable to offset the loss of out-of-work welfare benefits with gains in earnings. This suggests that the desired effects of the workfare reform were associated with the side-effects of income loss and increased poverty among a substantial number of lone mothers with insurmountable employment barriers. This finding stands in stark contrast to evidence from similar policy changes in Canada, the UK, and the US, and underscores that policymakers from other developed countries should be cautious when drawing lessons from the successful welfare reforms implemented in Anglo-Saxon countries.lone mothers, workfare reform, difference-in-differences, heterogeneity, earnings, labor force participation, poverty, disposable income

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 (2009) introduced two alternative sequences of nested dominance criteria for Lorenz curves which was 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. From the weight-functions of these inequality measures we obtain 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.Lorenz curve, Lorenz dominance, rank-dependent measures of inequality, Gini coefficient, generalized Gini families of inequality measures

On the Measurement of Long-Term Income Inequality and Income Mobility

This paper proposes a two-step aggregation method for measuring long-term income inequality and income mobility, where mobility is defined as an equalizer of long-term income. First, the income stream of each individual is aggregated into a measure of permanent income, which accounts for the costs associated with income fluctuations. Consequently, mobility will have an unambiguously positive impact on social welfare in the sense that for two societies that have identical short term income distributions, the social welfare will be greatest for the socie ty which exhibits most mobility. The second step consists of aggregating permanent incomes across individuals into measures of social welfare, inequality and mobility. To this end, we employ an axiomatic approach to justify the introduction of a generalized family of rank-dependent measures of inequality, where the distributional weights, as opposed to the Mehran-Yaari family, depend on income shares as well as on population shares. Moreover, a subfamily is shown to be associated with social welfare functions that have intuitively appealing interpretatio ns. Further, the generalized family of inequality measures provides several new interpretations of the Gini-coefficient. The proposed family of income mobility also proves to encompass standard measures of income mobility, depending on the assumptions made about the interpersonal preferences and the credit market.Income inequality, income mobility, social welfare, the Gini coefficient, permanent income, annuity.

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 (2009) introduced two alternative sequences of nested dominance criteria for Lorenz curves which was 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. From the weight-functions of these inequality measures we obtain 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.The Lorenz curve, Lorenz dominance, rank-dependent measures of inequality, the Gini coefficient, generalized Gini families of inequality measures.

No Child Left Behind: Universal Child Care and Children’s Long-Run Outcomes

There is a heated debate in the US, Canada and many European countries about introducing universally accessible child care. However, studies on universal child care and child development are scarce and only consider short-run outcomes. We analyze the introduction of universal child care in Norway, addressing the impact on children's long-run outcomes. Our precise and robust difference-in-difference estimates show that child care had strong positive effects on children's educational attainment and labor market participation, and also reduced welfare dependency. Subsample analysis indicates that children with low educated mothers and girls benefit the most from child care.universal child care, child development, long-run outcomes

Linearity in Instrumental Variables Estimation: Problems and Solutions

The linear IV estimator, in which the dependent variable is a linear function of a potentially endogenous regressor, is a major workhorse in empirical economics. When this regressor takes on multiple values, the linear specification restricts the marginal effects to be constant across all margins. This paper investigates the problems caused by the linearity restriction in IV estimation, and discusses possible remedies. We first examine the biases due to nonlinearity in the commonly used tests for non-zero treatment effects, selection bias, and instrument validity. Next, we consider three applications where theory suggests a nonlinear relationship, yet previous research has used linear IV estimators. We find that relaxing the linearity restriction in the IV estimation changes the qualitative conclusions about the relevant economic theory and the effectiveness of different policies.linear model, variable treatment intensity, nonlinearity, instrumental variables

On the Definition and Measurement of Chronic Poverty

As an alternative to the conventional methods for measuring chronic poverty, this paper proposes to use an interpersonal comparable measure of permanent income as a basis for defining and measuring chronic poverty. This approach accounts for the fact that individuals may undertake inter-period income transfers if it is to their advantage. Moreover, it allows for individual-specific interest rates on borrowing and saving as well as for the presence of liquidity constraints. Due to its general nature the proposed method proves useful for evaluating the theoretical basis of the standard methods for measuring chronic poverty.Intertemporal choice, liquidity constraints, permanent income, chronic poverty.

Older or Wealthier? The Impact of Age Adjustment on Cross-Sectional Inequality Measures.

Differences in individual wealth holdings are widely viewed as a driving force of economic inequality. However, as this finding relies on cross-section data, a concern is that one confuses older with wealthier. We propose a new method to adjust for age effects in cross-sections, which eliminates wealth inequality due to age, yet preserves inequality arising from other factors. Using a new cross-country comparable database, we examine the impact of age adjustments on wealth inequality across countries and over time. We find that the most widely used method yield a substantially different picture of age adjusted wealth inequality than our method.Wealth inequality; Life cycle; Age adjustments; Gini coefficient.