The Atkinson Inequality Measure and its Sampling Properties: Bayesian and Classical Approaches

This paper examines several Bayesian methods of obtaining posterior probability density functions of the Atkinson inequality measure and its associated social welfare function, in the context of grouped income distribution data. The methods are compared with asymptotic standard errors. The role of the number of income classes is investigated using a simulated distribution. If only a small number of groups is available in published data, there is a clear gain from generating the posterior probability density function when using an explicit income distribution assumption. Even with a small number of groups, the Bayesian approach gives results that are close to the sample values obtained using the corresponding individual observations.     

Taxation and national insurance contributions in Britain

It has often been suggested that National Insurance contributions and income taxation should be integrated in Britain, although the implications for the appropriate tax rates have not usually been examined in any detail. The complexity of the British National Insurance system means that the implications are not immediately clear. This paper examines the changes in tax rates which would be required to maintain total revenue at a constant level, and the tax rates required to support a minimum level of post-transfer income.     

Take–up of Means–tested Benefits and Labour Supply

This paper examines take–up rates in a model in which there is a fixed non–refundable cost of applying for benefits. The model involves a joint decision regarding both labour supply and the take–up of the benefit. There is a single means–tested benefit involving a 'taper rate' at which benefits are withdrawn as earnings increase. It is found that take–up increases as the level of the taper rate increases, and the value of benefits increases. The achievement of 100% take–up is associated with labour supply responses whereby there are few, if any, individuals who are both working and eligible for benefits. The results have implications for the effects of lowering the taper rate on the costs and effective targeting of benefits.     

Behavioural Microsimulation with Labour Supply Responses

This paper provides a technical survey of recent developments in behavioural microsimulation. We discuss the criteria by which models of labour supply may be chosen for application to behavioural microsimulation, and consider how such models may be augmented to control for fixed costs, child–related work costs, preference heterogeneity and endogeneity in wages. We describe methods by which non–linear budget constraints may be accommodated in estimation, policy simulations and welfare analysis, and discuss how stochastic terms may be factored into the simulation of behavioural responses to a policy shock.     

Decomposing Redistributive Effects of Taxes and Transfers in Australia: Annual and Lifetime Measures

This paper decomposes the redistributive effect on annual and lifetime inquality of a range of taxes and transfers in Australia, using a dynamic cohort lifetime simulation model. The redistributive effect is decomposed into vertical, horizontal and reranking effects. Horizontal inequities in the tax and transfer system are found to be negligible. The extent of reranking is greater in the lifetime than in the annual context and is affected by the equivalence scales used to adjust household incomes. If no adjustment is made to household incomes, reranking is about nine per cent of the reduction in lifetime inequality. However, if each child is counted as equivalent to one-third of an adult, reranking is found to be less than one per cent.     

The Redistributive Effects of a Minimum Wage Increase in New Zealand: A Microsimulation Analysis

This paper examines the potential effects on inequality and poverty of a minimum wage increase, based on a microsimulation model that captures the details of household composition and the income tax and welfare benefit system and allows for labour supply responses. Results suggest that, largely due to the composition of household incomes, a policy of increasing the minimum wage has a relatively small effect on the inequality of income per adult equivalent person, and a money metric utility measure, using several inequality indices. Hence, the minimum wage policy does not appear to be particularly well targeted, largely due to many low wage earners being secondary earners in higher income households, while many low income households have no wage earners at all. These results are reinforced when allowing for wage spillovers further up the wage distribution. Nevertheless, a minimum wage increase can have a more substantial effect on some poverty measures for sole parents in employment.     

Is external research assessment associated with convergence or divergence of research quality across universities and disciplines? Evidence from the PBRF process in New Zealand

ABSTRACT

Performance-based research evaluations have been adopted in several countries both to measure research quality in higher education institutions and as a basis for the allocation of funding across institutions. Much attention has been given to evaluating whether such schemes have increased the quality and quantity of research. This paper examines whether the introduction of the New Zealand Performance-Based Research Fund process produced convergence or divergence in measured research quality across universities and disciplines between the 2003 and 2012 assessments. Two convergence measures are obtained. One, referred to as β-convergence, relates to the relationship between changes in average quality and the initial quality level. The second concept, referred to as σ-convergence, relates to the changes in the dispersion in average research quality over time. Average quality scores by discipline and university were obtained from individual researcher data, revealing substantial β- and σ-convergence in research quality over the period. The hypothesis of uniform rates of convergence across almost all universities and disciplines is supported. The results provide insights into the incentives created by performance-based funding schemes.     

Income Mobility, Inequality and Social Welfare

It is often argued that an observation of rising annual income inequality need not have negative normative implications. The argument is that if there has been a sufficiently large simultaneous increase in mobility, the inequality of income measured over a longer time period can be lower despite the rise in annual inequality. In this paper, it is shown by example that if normative implications are drawn from a standard social welfare function, the set of circumstances put forward in the above argument are not sufficient to guarantee that social welfare will improve. The reason is that even though rising mobility does reduce longer term inequality, it also increases the variability of income profiles over time and the latter has a detrimental social welfare effect. Hence, there are two types of mobility: one which reduces inequality (regression to the mean), but another that increases inequality (relative movements uncorrelated with incomes). Further, if individuals' aversion to income variabiltiy is sufficiently larger than the social welfare judge's aversion to inequality, then an increase in mobility, no matter how large, cannot offset the negative normative effect of rising annual inequality.