A modified random-effect procedure for combining risk difference in sets of 2×2 tables from clinical trials

Summary Meta-analyses of sets of clinical trials often combine risk differences from several 2×2 tables according to a random-effects model. The DerSimonian-Laird random-effects procedure, widely used for estimating the populaton mean risk difference, weights the risk difference from each primary study inversely proportional to an estimate of its variance (the sum of the between-study variance and the conditional within-study variance). Because those weights are not independent of the risk differences, however, the procedure sometimes exhibits bias and unnatural behavior. The present paper proposes a modified weighting scheme that uses the unconditional within-study variance to avoid this source of bias. The modified procedure has variance closer to that available from weighting by ideal weights when such weights are known. We studied the modified procedure in extensive simulation experiments using situations whose parameters resemble those of actual studies in medical research. For comparison we also included two unbiased procedures, the unweighted mean and a sample-size-weighted mean; their relative variability depends on the extent of heterogeneity among the primary studies. An example illustrates the application of the procedures to actual data and the differences among the results. This research was supported by Grant HS 05936 from the Agency for Health Care Policy and Research to Harvard University.     

Sexual identity in the ghetto

The more things change, the worse they get.Presented April 18, 1991, Duke University, at the Department of Psychiatry's Grand Rounds, this paper condenses, integrates and updates the author's earlier publication. Acknowledgement and thanks for funding and professional sponsorship of the four research studies this paper draws from are selectively due to the Eugene and Agnes E. Meyer Foundation, the Edgar Stern Family Fund, The National Institute for Mental Health, the Baltimore-Washington Institute for Psychoanalysis and the Department of Psychiatry, Children's Hospital National Medical Center.     

Interracial rape: Examining the increasing frequency argument

A number of researchers have recently challenged the long-held notion among criminologists that rape, along with most other violent crimes, is an intraracial crime. Based on analysis of survey data they concluded that black rapists “prefer” or “seek out” white victims and that the likelihood of a black offender selecting a white victim has been increasing during recent years. Data presented here (1977–88 National Crime Surveys) refute the notion that black rapists “prefer” white victims. Moreover these same data fail to support the contention that rapes involving black offenders and white victims have been increasing. According to National Crime Survey estimates, the proportion of black offenders that victimize whites has been declining. An earlier version of this paper was presented at the annual meetings of the American Society of Criminology, November 1991.     

Screening for patients with alcohol problems: severity of patients identified by the CAGE.

Primary care physicians are well situated to identify patients with substance abuse problems and motivate them to seek appropriate assistance, but active programs are the exception. A study in a community setting was undertaken to assess the CAGE (the first letters of key words in a series of four questions about drinking: cut down; annoyed; guilty; and eye-opener), instrument in the routine screening for alcohol problems in both new and established patients. The screening process identified subjects for a pilot evaluation of a motivational interview designed to encourage problem-solving behavior. This article focuses on the screening results and the use of the CAGE instrument. During June and July of 1990, 687 patients of two primary care physicians belonging to a large group practice were asked to complete a health questionnaire that included the CAGE. Those who responded affirmatively to at least two of the four CAGE questions were requested to participate in follow-up assessment of problems associated with alcohol and health. The type and severity of alcohol problems experienced by patients who scored positive on the CAGE are described. Prevalence of a positive score on the CAGE was 8.6 percent with males, smokers, and blue collar and unemployed persons being more likely to score positive. The positive predictive value was .68. Primarily, persons with moderate alcohol problems were identified. Results show that the CAGE instrument is a useful screening device for identifying those with mild to moderate substance abuse problems, increasing the opportunity for intervention prior to serious medical complications. The instrument is easily administered, and has demonstrated relatively high levels of sensitivity and specificity. When combined with assessment and motivational interviews, the CAGE shows promise in the secondary prevention of substance abuse and related health problems.     

Defining child abuse in Hong Kong

Definitions of child abuse are culturally driven. Hong Kong, with a predominantly Chinese population, has managed to eradicate much of the societal abuse that children suffer elsewhere in Asia. Professional and government attention has now shifted to child abuse and neglect within the family. The paper, based on interviews with key professionals. analysis of policy documents and practice records examines traditional Chinese parent-child relationships. the status of parental authority and corporal punishment and changes in contemporary Hong Kong family life. It goes on to outline the development of responses to child abuse in Hong Kong, some of the dilemmas that professionals face in defining abuse and areas for future research.     

Generalized Laplacian approximations in Bayesian inference

This paper presents a new Laplacian approximation to the posterior density of η = g(θ). It has a simpler analytical form than that described by Leonard et al. (1989). The approximation derived by Leonard et al. requires a conditional information matrix R_η to be positive definite for every fixed η. However, in many cases, not all R_η are positive definite. In such cases, the computations of their approximations fail, since the approximation cannot be normalized. However, the new approximation may be modified so that the corresponding conditional information matrix can be made positive definite for every fixed η. In addition, a Bayesian procedure for contingency-table model checking is provided. An example of cross-classification between the educational level of a wife and fertility-planning status of couples is used for explanation. Various Laplacian approximations are computed and compared in this example and in an example of public school expenditures in the context of Bayesian analysis of the multiparameter Fisher-Behrens problem.     

Will taxpayers ever like taxes?: Responses to the U.S. Tax Reform Act of 1986

Major policy changes like the 1986 Tax Reform Act (TRA) in the United States provide natural experiments to study attitudinal and behavior responses to law. Surprisingly, public evaluations of the TRA became increasingly negative after passage, while general support for the tax system became more positive in response to the changes. To explain this puzzle, we propose a dynamic model of taxpayer attitudes that is consistent with the observed loose linkage between logically-connected concepts. We briefly review the political context, objectives and impacts of the 1986 Tax Reform Act, and present several studies testing the impact of self-interest, prior beliefs, and social discussion on changes in attitudes and behavior.Results suggest that the complexity of taxes and difficulty in knowing objective impacts weakens the role of self-interest in attitudinal changes, thereby strengthening the role of prior beliefs and discussion. Evaluations of tax laws are most responsive to more politically-oriented influences.     

“WHAT DOES SHE SEE IN HIM?”: THE EFFECT OF SHARING ON THE CHOICE OF SPOUSE

All husbands and wives share in the spoils of marriage. Sharing makes each partner a residual claimant and encourages spouses to provide marital inputs. However, because each spouse is only a partial residual claimant, each may be inclined to provide a "suboptimal" level of marital inputs. The choice of spouse influences the level of distortion, and under some circumstances the efficient mating is between individuals of equal value