Aydogan Ulker

Robustness in health research: Do differences in health measures, techniques, and time frame matter?

Survey-based health research is in a boom phase following an increased amount of health spending in OECD countries and the interest in ageing. A general characteristic of survey-based health research is its diversity. Different studies are based on different health questions in different datasets; they use different statistical techniques; they differ in whether they approach health from an ordinal or cardinal perspective; and they differ in whether they measure short-term or long-term effects. The question in this paper is simple: do these differences matter for the findings? We investigate the effects of life-style choices (drinking, smoking, exercise) and income on six measures of health in the US Health and Retirement Study (HRS) between 1992 and 2002: (1) self-assessed general health status, (2) problems with undertaking daily tasks and chores, (3) mental health indicators, (4) BMI, (5) the presence of serious long-term health conditions, and (6) mortality. We compare ordinal models with cardinal models; we compare models with fixed effects to models without fixed-effects; and we compare short-term effects to long-term effects. We find considerable variation in the impact of different determinants on our chosen health outcome measures; we find that it matters whether ordinality or cardinality is assumed; we find substantial differences between estimates that account for fixed effects versus those that do not; and we find that short-run and long-run effects differ greatly. All this implies that health is an even more complicated notion than hitherto thought, defying generalizations from one measure to the others or one methodology to another.

Air Pollution and Infant Mortality: Evidence from the Expansion of Natural Gas Infrastructure

Natural gas has emerged as an increasingly attractive source of energy since it is highly efficient, abundant, and cleaner than any other fossil fuel. In this paper, we examine the impact of widespread adoption of natural gas as a source of fuel on infant mortality in Turkey, using variation across provinces and over time in the intensity of natural gas utilization. Our estimates indicate that the expansion of natural gas infrastructure has resulted in a significant decrease in the rate of infant mortality. Specifically, a one-percentage point increase in natural gas intensity - measured by the rate of subscriptions to natural gas services - would cause the infant mortality rate to decrease by 3.9 percent, which would translate into approximately 340 infant lives saved in 2011 alone.

Private health insurance status and utilisation of dental services in Australia

This article focuses on the relationship between private insurance status and dental service utilisation in Australia using data between 1995 and 2001. This article employs joint maximum likelihood to estimate models of time since last dental visit treating private ancillary health insurance (PAHI) as endogenous. The sensitivity of results to the choice between two different but related types of instrumental variables is examined. We find robust evidence in both 1995 and 2001 that individuals with a PAHI policy make significantly more frequent dental consultations relative to those without such coverage. A comparison of the 1995 and 2001 results, however, suggests that there has been an increasing role of PAHI in terms of the frequency of dental consultations over time. This seems intuitive given the trends in the price of unsubsidised private dental consultations. In terms of policy, our results suggest that while government measures to increase private health insurance coverage in Australia have been successful to a significant degree, that success may have come at some cost in terms of socio-economic inequality as the privately insured are provided much better access to care and financial protection.

Determinants of Maternity Leave Duration in Australia: Evidence from the Hilda Survey

We use the first five waves of the Household, Income and Labour Dynamics in Australia survey to examine what determines the maternity leave taken by pre-birth employed mothers of newborn children in Australia. We find that the difficulties faced by mothers in finding appropriate child care in terms of both cost and quality hinder them from returning to the labour market following childbirth. Maternity leave entitlements lead to an earlier return to the labour market following the birth of a child, relative to those who have no leave rights at all. Mothers with higher wages in their pre-birth employment and mothers with higher education levels tend to return to the labour market earlier than their lower wage and less educated counterparts. More flexible pre-birth jobs are associated with an increase in the likelihood of mothers returning to the workforce earlier than the average. Household wealth, however, seems to play a facilitating role in mothers taking a longer period of maternity leave to look after the newborn child. That is, mothers who have higher wealth levels can ‘afford’ to stay on maternity leave longer, to look after their children better during their primary developmental months. We believe that this article provides useful insights into the employment transitions of Australian mothers after having a baby.

Household Composition and Housing Expenditures in Rental-Occupied and Owner-Occupied Markets

This article examines the relationship between household compositions and housing expenditures in rental-occupied and owner-occupied markets. The author finds that renters allocate their budget proportionately between housing and nonhousing goods for an additional household member, leaving the budget share of housing expenditures unchanged. For homeowners, nevertheless, an extra member implies a reduction in housing expenditures as a share of total budget. Although age and gender compositions turn out to be significant in determining the budget share of housing expenditures for renters, they play no major role for homeowners. And although an increase in the number of working members for renters significantly reduces the share of budget spent on housing, it has no significant impact for their owner counterparts. Moreover, keeping total expenditures constant, the main income source of the head of the household does not make any difference in terms of resource allocation across housing and nonhousing goods for both renters and owners.

Body size at birth, physical development and cognitive outcomes in early childhood: evidence from the Longitudinal Survey of Australian Children

Using a rich sample created from the Longitudinal Survey of Australian Children, we investigate the extent to which the relationship between body size at birth and early childhood cognitive skills is mediated by physical development indicators. Consistent with existing evidence from other countries, we find a significant relationship between body size at birth and future development among Australian children as well, in terms of both weight and length. Accounting for progressive measures of physical developments and other confounding factors, however, indicates that only a small proportion of this association works through these pathways, while most of it remains persistent.

Can natural gas save lives? Evidence from the deployment of a fuel delivery system in a developing country

There has been a widespread displacement of coal by natural gas as space heating and cooking technology in Turkey in the last two decades, triggered by the deployment of natural gas networks. We examine the impact of this development on mortality among adults and the elderly by exploiting the variation in the timing of the deployment and the intensity of expansion of gas networks across provinces using data from 2001 to 2016. The results indicate that the expansion of natural gas has caused significant reductions in mortality among both adults and the elderly. These findings are supported by our auxiliary analysis, which demonstrates that the expansion of natural gas networks might have led to a significant improvement in air quality. Furthermore, we show that the mortality gains are primarily driven by reductions in cardio-respiratory deaths, which are more likely to be due to conditions caused or exacerbated by air pollution.

Win at All Costs or Lose Gracefully in High-Stakes Competition? Gender Differences in Professional Tennis

This article examines line-call challenges by male and female professional tennis players in major tournaments around the world. In terms of utilization rates, we find that the genders behave similarly. Nevertheless, we do detect some intriguing gender differences in these challenges. First, male players’ challenges are more likely to be provoked by those of their opponents. More importantly, at tiebreaks, females are more likely to reverse an umpire’s unfavorable call, while males make relatively more unsuccessful challenges. Furthermore, we find that men are a lot more likely to make “embarrassing” line-call challenges at tiebreaks and offenses (i.e., when the shot lands at the opponent’s side of the tennis court) than women. These significant gender differences suggest that women particularly diverge from men at crucial junctures of the match such as tiebreaks. Differences in factors such as risk aversion, overconfidence, pride, shame, and strategic signalling behavior might help us to explain these gender-difference findings in line call challenges.