David Madden

Sample Selection Versus Two-Part Models Revisited: the Case of Female Smoking and Drinking

There is a well-established debate between Heckman sample selection and two-part models in health econometrics, particularly when no obvious exclusion restrictions are available. Most of this debate has focussed on the application of these models to health care expenditure. This paper revisits the debate in the context of female smoking and drinking, and evaluates the two approaches on three grounds: theoretical, practical and statistical. The two-part model is generally favoured but it is stressed that this comparison should be carried out on a case-by-case basis.

Labour market discrimination on the basis of health: an application to UK data

An analysis of wage discrimination is carried out on the basis of health on UK data with a number of important modifications. First selection is controlled for into both health and labour market status. Second the direct effect of health upon productivity is accounted for and third, discrimination is examined with regard to participation as well as wages. The question of selection into health status is found to be of little empirical importance but taking account of selection into labour market status and the direct impact of health upon productivity leads to a fall in measured discrimination. The paper finds similar results with regard to participation. It is also examined whether these effects differ across age and gender.

Ordinal and cardinal measures of health inequality : an empirical comparison

When measuring health inequality using ordinal data, analysts typically must choose between indices specifically based upon ordinal data and more standard indices using ordinal data, which has been transformed into cardinal data. This paper compares inequality rankings across a number of different approaches and finds considerable sensitivity to the choice between ordinal- and cardinal-based indices. There is relatively little sensitivity to the ethical choices made by the analyst in terms of the weight attached to different parts of the distribution.

Tobacco taxes and starting and quitting smoking: does the effect differ by education?

This article uses duration analysis to investigate the role of tobacco taxes in starting and quitting smoking. Applying a variety of parametric duration models to a sample of Irish women, it finds that in general tobacco taxes do influence starting and quitting smoking in the expected direction. It also finds that the effect for starting differs by education but in a nonmonotonic way, with the greatest effect for women with intermediate levels of education. The results for quitting suggest the greatest effect for women with the lowest level of education. These results are unchanged when account is taken of unobserved heterogeneity.

LABOUR SUPPLY, COMMODITY DEMAND AND MARGINAL TAX REFORM*

This paper examines the implications of extending the Ahmad-Stern (1984) model of indirect tax reform to include labor supply. The inclusion of labor supply alters the basic measure of marginal revenue cost of indirect taxation and introduces the possibility of calculating a marginal revenue cost for direct taxation. The paper derives the expressions for these revised marginal revenue costs and provides estimates from Irish data. It then examines the sensitivity of the results to assumptions regarding functional form and, in particular, goods/leisure separability. Copyright 1995 by Royal Economic Society.

Mental stress in Ireland, 1994–2000: a stochastic dominance approach

The General Health Questionnaire (GHQ) is frequently used as a measure of mental well-being with those people with values below a certain threshold regarded as suffering from mental stress. Comparison of mental stress levels across populations may then be sensitive to the chosen threshold. This paper uses stochastic dominance techniques to show that mental stress fell in Ireland over the 1994-2000 period regardless of the threshold chosen. Decomposition techniques suggest that changes in the proportion unemployed and in the protective effect of income, education and marital status upon mental health were the principal factors underlying this fall.

The use of lamotrigine, vigabatrin and gabapentin as add-on therapy in intractable epilepsy of childhood

PURPOSE Lamotrigine (LTG), vigabatrin (VGB) and gabapentin (GBP) are three anti-epileptic drugs (AEDs) used in the treatment of children with epilepsy for which long-term retention rates are not currently well known. This study examines the efficacy, long-term survival and adverse event profile of these three agents used as add-on therapy in children with refractory epilepsy over a 10-year period. METHODS Three separate audits were conducted between February 1996 and September 2000. All children studied had epilepsy refractory to other AEDs. Efficacy was confirmed if a patient became seizure free or achieved >50% reduction in seizure frequency for 6 months or more after starting therapy. Adverse events and patient survival for each drug were recorded at the end of the study period. RESULTS Between September 1990 and February 1996, 132 children received LTG, 80 VGB and 39 GBP. At the 10-year follow-up audit, 33% of the children on LTG had a sustained beneficial effect on their seizure frequency in contrast to 19% for VGB and 15% for GBP. No significant difference in efficacy was found in children with partial seizures. Children with epileptic encephalopathy (EE) including myoclonic-astatic epilepsy and Lennox-Gastaut Syndrome (LGS) achieved a more favorable response to LTG. The main reasons for drug withdrawal were lack of efficacy for VGB, apparent worsening of seizures for GBP and the development of a rash for LTG. CONCLUSIONS Lamotrigine is a useful add-on therapy in treating children with epilepsy. It has a low adverse event profile and a sustained beneficial effect in children with intractable epilepsy.

The poverty effects of a 'fat-tax' in Ireland.

To combat growing levels of obesity, health-related taxes have been suggested with taxes on foods high in fat or sugar. Such taxes have been criticised on the basis of their regressivity and potentially adverse impact upon poverty. This paper analyses the effect of such taxes on a range of poverty measures and also examines the effect of a revenue-neutral tax subsidy mixed with a tax on unhealthy food combined with a subsidy on more healthy food. Using Irish expenditure data, the results indicate that taxes on high fat/sugar goods on their own will be regressive but that a tax-subsidy combination can be broadly neutral with respect to poverty.

The Relationship Between Low Birthweight and Socioeconomic Status in Ireland

There is now fairly substantial evidence of a socioeconomic gradient in low birth weight for developed countries. The standard summary statistic for this gradient is the concentration index. Using data from the recently published Growing Up in Ireland survey, this paper calculates this index for low birth weight arising from preterm and intrauterine growth retardation. It also carries out a decomposition of this index for the different sources of low birth weight and finds that income inequality appears to be less important for the case of preterm births, while fathers education and local environmental conditions appear to be more relevant for intrauterine growth retardation. The application of the standard Blinder-Oaxaca decomposition also indicates that the socioeconomic gradient for low birth weight appears to arise owing to different characteristics between rich and poor, and not because the impact of any given characteristic on low birth weight differs between rich and poor.

Towards a broader explanation of male-female wage differences

Most analyses of wage discrimination have followed the traditional Blinder-Oaxaca decomposition of wage differences into endowment and discrimination components. This approach has neglected the possibility of wage discrimination at point of entry to the labour market and also the issue of selectivity bias. Using some recently developed techniques of Neumann and Oaxaca this paper decomposes male-female wage differences taking account of discrimination in terms of access to the labour market and also selectivity bias. It finds considerable evidence of discrimination at point of entry but that discrimination owing to selectivity bias is minimal.