THE RELATIONSHIP BETWEEN CHILD HEALTH,DEVELOPMENTAL GAPS,AND PARENTAL EDUCATION: EVIDENCE FROM ADMINISTRATIVE DATA

We use administrative German data to examine the role of physical and mental health conditions in explaining developmental gaps between children whose parents have different educational levels. Specifically, we employ sibling fixed effect models to estimate the effect of a comprehensive list of childhood health conditions—diagnosed by government physicians—on the cognitive and verbal ability of pre‐school children. We also apply decomposition methods to examine the extent to which gaps in child development can be attributed to child health conditions. While most physical health conditions have small and insignificant effects, mental health conditions, in particular hyperactivity, have a large and significant effect on development. Mental health conditions account for 14%–36% of the gap in cognitive ability and for 23%–24% of that in verbal ability. Thus, policies aimed at reducing disparities in child development and socioeconomic inequalities later in life should focus more on the early diagnosis and effective treatment of mental health conditions.     

ROUTES OF INFECTION: EXPORTS AND HIV INCIDENCE IN SUB‐SAHARAN AFRICA

This paper estimates whether exports affect the incidence of HIV in Africa. This relationship has implications for HIV prevention policy as well as for the consequences of trade increases in Africa. I estimate this impact using two sources of data on HIV incidence, one generated based on UNAIDS estimates and the other based on observed HIV mortality. These data are combined with data on export value and volume. I find a fairly consistent positive relationship between exports and new HIV infections: doubling exports leads to a 10%–70% increase in new HIV infections. Consistent with theory, this relationship is larger in areas with higher baseline HIV prevalence. I interpret the result as suggesting that increased exports increase the movement of people (trucking), which increases sexual contacts. Consistent with this interpretation, the effect is larger for export growth than for income growth per se and is larger in areas with more extensive road networks.     

Joint decisions on household membership and human capital accumulation of youths. The role of expected earnings and local markets

This paper analyses the effects of expected earnings and local markets conditions on the behaviour of young adults with high school diplomas. Decisions to either remain in the parental home or form a new household are modelled jointly with those of either gaining work experience or investing in a university education. Expected lifetime earnings are found to play a crucial role in determining the choice of studying and residing with parents. Poor labour market opportunities discourage young people from working and induce them to study. The cost of housing greatly influences the choice of working and leaving the parental home. Received: 23 March 2001/Accepted: 26 November 2001 All correspondence to Gianna Claudia Giannelli. Helpful comments by two anonymous referees are gratefully acknowledged. Responsible editor: John F. Ermisch.     

TRADE QUOTAS AND BUYER POWER,WITH AN APPLICATION TO THE E.U. NATURAL GAS MARKET

We consider a market in which domestic buyers negotiate contracts with foreign sellers, and explore how trade quotas can help to increase the buyers' countervailing power. We use the Shapley value to describe bargaining power and the distribution of the trade surplus in such a bilateral oligopoly. By exploiting strategic externalities among the buyers, bilateral trade quotas can improve the buyers' bargaining positions. In contrast, aggregate trade restrictions on all buyers' trade never improve buyer surplus. Minimum quotas on imports from fringe suppliers can benefit nonaffected buyers, as these enjoy positive externalities. We apply these insights to the E.U. market for natural gas and show that the effects of trade quotas on E.U. gas importers' power can be significant.     

SALES AND COLLUSION IN A MARKET WITH STORAGE

Sales are a widespread and well‐known phenomenon documented in several product markets. This paper presents a novel rationale for sales that does not rely on consumer heterogeneity, or on any form of randomness to explain such periodic price fluctuations. The analysis is carried out in the context of a simple repeated price competition model, and establishes that firms must periodically reduce prices in order to sustain collusion when goods are storable and the market is large. The largest equilibrium profits are characterized at any market size. A trade‐off between the size of the industry and its profits arises. Sales foster collusion, by magnifying the inter‐temporal links in consumers' decisions.     

Subjective measures of risk aversion, fixed costs, and portfolio choice

The paper investigates risk preferences among different types of individuals. We use several different measures of risk preferences, including questions on choices between uncertain income streams suggested by Barsky, Juster, Kimball, and Shapiro (1997) and a number of ad hoc measures. As in [Barsky et al., 1997] and [Arrondel and Calvo-Pardo, 2002], we first analyze individual variation in the risk aversion measures and explain them by background characteristics (both “objective” characteristics and other subjective measures of risk preference). Next we incorporate the measured risk preferences into a household portfolio allocation model, which explains portfolio shares, while accounting for incomplete portfolios and fixed costs. Our results show that a measure based on factor analysis of answers to a number of simple risk preference questions has the most explanatory power. The Barsky et al. (1997) measure has less explanatory power than this “a-theoretical” measure, suggesting that sophisticated measures based on economic theory may exceed the financial capability of respondents. Fixed costs turn out to provide an economically and statistically highly significant explanation for incomplete portfolios.     

Debiasing or rebiasing? Moderating the illusion of delayed incentives

This paper studies corrective strategies for the illusion of delayed incentives (Soman, 1998), the phenomena that money-for-effort transactions that are unattractive in the present appear attractive when they are in the future. This illusion occurs because future effort is discounted more heavily than future monetary outcomes. In this research, we show that this bias of differential discounting can be corrected by asking consumers to perform effort at the time of decision-making. We further outline three explanations for why this intervention attenuates the illusion of delayed incentives, and discuss whether these explanations constitute a debiasing effect or a rebiasing effect (Larrick, 2004). We report the results of two laboratory experiments and discuss theoretical and practical implications of our findings.     

Full-time, part-time employment and life satisfaction of the elderly

There is continued interest in employment and subjective well-being among the elderly because of the increasing proportion of elderly population in the labor force. This study investigates the association between part-time and full-time employment and life satisfaction of the elderly in Taiwan. We also examine how these associations may differ across socio-demographic groups. An ordinal treatment effect model is developed to accommodate the discrete feature of the employment decision and the potential endogeneity of these two outcomes. Using a unique sample of the elderly in Taiwan, in contrast to findings for the general population of the previous studies, we find that part-time employment is significant and positively associated with life satisfaction, while elderly with full-time employment have lower life satisfaction. These results are robust across socio-demographic groups.     

上海“十二五”城市建设方针和重点领域探讨

改革开放以来,上海城市建设的重心一直在中心城区。世博会后,城市建设的重心必将逐步转移至城郊地区。同时,上海已进入工业化后期阶段,只有统筹城郊发展,加快郊区建设步伐,才能在新起点上实现新飞跃。“十二五”时期上海城市建设方针应是“郊区为主,聚焦新城;生态优先,宜居为重;城乡统筹,协调发展”,聚焦综合性新城、农村基础设施等重点领域的投资建设。     

12-h workdays: current knowledge and future directions

Work schedules other than those based on the traditional 8-h workday duration have become much more common in recent years. Many such schedules compress the work week into three or four longer workdays and include an increased number of days off. In particular, rosters based on 12-h workdays have gained in popularity, and such rosters have been the focus of considerable research. The literature on 12-h workdays is, however, full of inconsistencies. Not surprisingly, there is considerable evidence from some of these studies that 12-h shifts tend to cause more fatigue than 8-h shifts. This extra fatigue may be associated with lower work efficiency, and with more errors and accidents. There is also strong evidence that workers prefer 12-h shifts due to some perceived advantages. The present paper reviews and examines these studies and their findings and discusses some possible reasons for the apparent contradictions in reported findings. Directions for decision makers and future research are suggested.