Improved Fisher z estimators for univariate random‐effects meta‐analysis of correlations

Several authors have studied or used the following estimation strategy for meta‐analysing correlations: obtain a point estimate or confidence interval for the mean Fisher z correlation, and transform this estimate to the Pearson r metric. Using the relationship between Fisher z and Pearson r random variables, I demonstrate the potential discrepancy induced by directly z‐to‐r transforming a mean correlation parameter. Point and interval estimators based on an alternative integral z‐to‐r transformation are proposed. Analytic expressions for the expectation and variance of certain meta‐analytic point estimators are also provided, as are selected moments of correlation parameters; numerical examples are included. In an application of these analytic results, the proposed point estimator outperformed its usual direct z‐to‐r counterpart and compared favourably with an estimator based on Pearson r correlations. Practical implications, extensions of the proposed estimators, and uses for the analytic results are discussed.     

Permanence and change in memory II. Reproduction of words in sentences

Abstract.— A retroactive interference paradigm was employed for studying qualitative memory changes. Sentences, containing an ambiguous word that was defined differently by succeeding words, were used as stimulus material. Such retroactive definitions of meaning were found to lead to qualitative changes in reproduction. It is suggested that the issue of permanence and change in memory may be related to the choice of lists of independent items or contextual units as stimulus material. A contextual theory of memory, implying the conception of memory in a stream, is advocated.     

How Discrimination Impacts Sociopolitical Behavior: A Multidimensional Perspective

The conventional wisdom regarding the impact of discrimination on political behavior is that the perception of prejudiced treatment motivates individuals to take political action. This study challenges this common conception by demonstrating that the source of discrimination can play a significant role in whether perceived or experienced injustice leads to activism or withdrawal from sociopolitical life. Drawing from political science and social psychology literature, this study provides a new perspective on the potential effects of discrimination on a relatively new marginalized group in the United States. Specifically, an important distinction is drawn between political (systematic) and societal (interpersonal) discrimination in analyzing the sociopolitical behavior of American Muslims in the aftermath of the 9/11 terrorist attacks. The results will hopefully encourage scholars to take a deeper look at the nexus between discrimination and democratic engagement, which is an important, complex, multidimensional, and understudied topic.     

Factors influencing racial comparisons of self-esteem: a quantitative review

Research on racial comparisons of self-esteem was examined. Early research in this area, exemplified by the doll studies of racial preference, was viewed as demonstrating that Blacks have less self-regard than Whites. However, a meta-analytic synthesis of 261 comparisons, based largely on self-esteem scales and involving more than half a million respondents, revealed higher scores for Black than for White children, adolescents, and young adults. This analysis further revealed that the direction and magnitude of racial differences are influenced by such demographic characteristics as participant age and socioeconomic status, as well as by characteristics of the measuring instruments. Many findings--for example, that the self-esteem advantage for Black respondents increases with age and is related to the sex composition of the sample--underscore the need for long-term longitudinal studies of self-esteem development in male and female members of both racial groups.     

Random‐effects meta‐analysis of correlations: Monte Carlo evaluation of mean estimators

Several authors have cautioned against using Fisher's z‐transformation in random‐effects meta‐analysis of correlations, which seems to perform poorly in some situations, especially with substantial inter‐study heterogeneity. Attributing this performance largely to the direct z‐to‐r transformation (DZRT) of Fisher z results (e.g. point estimate of mean correlation), in a previous paper Hafdahl (2009) proposed point and interval estimators of the mean Pearson r correlation that instead use an integral z‐to‐r transformation (IZRT). The present Monte Carlo study of these IZRT Fisher z estimators includes comparisons with their DZRT counterparts and with estimators based on Pearson r correlations. The IZRT point estimator was usually more accurate and efficient than its DZRT counterpart and comparable to the two Pearson r point estimators – better in some conditions but worse in others. Coverage probability for the IZRT confidence intervals (CIs) was often near nominal, much better than for the DZRT CIs, and comparable to coverage for the Pearson r CIs; every approach's CI fell markedly below nominal in some conditions. The IZRT estimators contradict warnings about Fisher z estimators' poor performance. Recommendations for practising research synthesists are offered, and an Appendix provides computing code to implement the IZRT as in the real‐data example.     

Free-response self-discrepancies across, among, and within FFM personality dimensions

An approach for personality-based self-discrepancy (PBSD) measurement is proposed, whereby self-beliefs and incongruities among their contents are assessed with respect to five-factor model (FFM) semantic dimensions. Selves Questionnaire attributes from 191 college students were coded against L. R. Goldberg's (1990) FFM factor analysis to construct personality scores for actual, ideal, and ought self domains, as well as several PBSD indices. Multivariate analyses were conducted to test self-discrepancy and personality-structure hypotheses, and to demonstrate this strategy's operational flexibility. Profile analyses indicated that empirical self-discrepancies depend upon whether and how personality structure is incorporated. Methodological alterations influenced self-discrepancy findings negligibly. Initial evidence for PBSD construct validity and predictive specificity is presented, and the approach's implications, advantages, and extensions are discussed.