Where are the motives? A problem with evidence in the work of Richard Thaler

In this journal (Mackenzie, 1997. Economic Psychology 18(1), 123–135), Mackenzie argues that there is a problem with Thaler's work: in failing to provide evidence about motives, Thaler's claims are vulnerable. In this comment, I present a different view. Thaler merely pinpoints some stylized facts, such as the endowment effect. Models of economic behaviour should be able to account for these. Mackenzie's discussion of the wine owner anecdote gives ad hoc reasons for apparently irrational behaviour. Thaler's work focuses on systematic effects, which is a much more fruitful approach. Mackenzie fails to do justice to the work that has been done to document the endowment effect.     

A modified bootstrap estimator for the mean of an asymmetric distribution

A modified bootstrap estimator of the population mean is proposed which is a convex combination of the sample mean and sample median, where the weights are random quantities. The estimator is shown to be strongly consistent and asymptotically normally distributed. The small- and moderate-sample-size behavior of the estimator is investigated and compared with that of the sample mean by means of Monte Carlo studies. It is found that the newly proposed estimator has much smaller mean squared errors and also yields significantly shorter confidence intervals for the population mean.     

Local Labor Markets and Caseload Decline in Louisiana in the 1990s*

Abstract Efforts to explain declines in welfare caseloads in the 1990s focus on three factors (economic opportunity, welfare policy, and demographic characteristics) and produce mixed results. Although several recent studies consider state differences, few consider local differences within states. Failure to control for caseload persistence and within‐state variation in program implementation may be one reason why studies produce contradictory results regarding the effect of economic conditions on caseload decline. Using data for Louisiana parishes from 1991 to 1998, we analyze local caseload decline. Our results support other researchers' finding of a “threat effect” before 1996 welfare reform; they indicate that, all else being equal, reducing caseloads will be most difficult in nonadjacent nonmetropolitan parishes and easiest in adjacent nonmetropolitan parishes.     

新世纪文学批评断想

回顾 2 0世纪中国文学批评曲折发展的历史 ,繁荣新世纪文学批评 ,一是要寻求批评的学理化 ,希望批评家在中西文化的交融、整合中加强自身批评原理的建构 ,保持批评话语的独立规范 ,力避批评的传媒化 ;二是要提倡批评的多样化 ,在批评方法、批评家类型、批评声音、批评文体等不同层面上实现真正的多姿多彩 ;三是力戒批评的意气化 ,希望批评家挣脱名缰利锁 ,排除怨恨心理 ,以平常心态对待批评对象     

Multilevel models for longitudinal variables prognostic for survival

The issue of modelling the joint distribution of survival time and of prognostic variables measured periodically has recently become of interest in the AIDS literature but is of relevance in other applications. The focus of this paper is on clinical trials where follow-up measurements of potentially prognostic variables are often collected but not routinely used. These measurements can be used to study the biological evolution of the disease of interest; in particular the effect of an active treatment can be examined by comparing the time profiles of patients in the active and placebo group. It is proposed to use multilevel regression analysis to model the individual repeated observations as function of time and, possibly, treatment. To address the problem of informative drop-out—which may arise if deaths (or any other censoring events) are related to the unobserved values of the prognostic variables—we analyse sequentially overlapping portions of the follow-up information. An example arising from a randomized clinical trial for the treatment of primary biliary cirrhosis is examined in detail.     

A method of choosing multiway partitions for classification and decision trees

A method is given of choosing k-way partitions (where 2 ≤ k ≤ (number of categories of predictor variable)) in classification or decision tree analyses. The method, like that proposed by Kass, chooses the best partition on the basis of statistical significanceand uses the Bonferroni inequality to calculate the significance. Unlike Kass's algorithm, the algorithm does not favour simple partitions (low values of k) nor does it discriminate against free-type (no restriction on order of values) predictor variables with many categories. A method of adjusting the significance for the number of predictor variables and of using multiple comparisons to put an upper bound on the significance is given. Monte Carlo tests show that the algorithm gives slightly conservative tests of significance for both small and large samples and does not favour one type of predictor variable over another. The algorithm is incoroporated in a PC software program, Knowledgeseeker,which is briefly described.     

Stress, physical activity and coronary heart disease

Recent years have witnessed an increasing popularity of corporate fitness programmes. Regular physical activity and, in particular, high aerobic fitness are associated with a lower risk of coronary heart disease. Apart from its beneficial effects on resting levels of blood pressure and cholesterol, fitness is believed to reduce the impact of psychological stress. This hypothesis has been put to the test in 33 studies examining the physiological stress response of groups selected to differ in their fitness level. Although some evidence was found for a reduced response to stress in high fit subjects, the effects were not very strong. During 54 confrontations with a stressful task, significantly lower heart rate reactions in high fit subjects were seen in only nine tasks (17%). With nine out of 36 stressors (28%), fit subjects showed a lower diastolic blood pressure response. However, in combination with a frequently found reduction in basal levels, the high fit showed a consistently favourable cardiovascular profile under stress. This adaptation may reflect the benefits of regular exercise over a more sedentary lifestyle, but a combined influence of genetic make-up on cardiovascular reactivity and fitness cannot be ruled out.