Repeated measures one‐way ANOVA based on a modified one‐step M‐estimator

Wilcox, Keselman, Muska and Cribbie (2000) found a method for comparing the trimmed means of dependent groups that performed well in simulations, in terms of Type I errors, with a sample size as small as 21. Theory and simulations indicate that little power is lost under normality when using trimmed means rather than untrimmed means, and trimmed means can result in substantially higher power when sampling from a heavy‐tailed distribution. However, trimmed means suffer from two practical concerns described in this paper. Replacing trimmed means with a robust M‐estimator addresses these concerns, but control over the probability of a Type I error can be unsatisfactory when the sample size is small. Methods based on a simple modification of a one‐step M‐estimator that address the problems with trimmed means are examined. Several omnibus tests are compared, one of which performed well in simulations, even with a sample size of 11.     

Comparing groups in a before–after design: When t test and ANCOVA produce different results

Background. Researchers often test people before and after some treatment and compare these scores with a control group. Sometimes it is not possible to allocate people into conditions randomly, which means the initial scores for the two groups may differ. There are two main approaches: t test on the gain scores and ANCOVA partialling out the initial scores. Lord (1967) showed that these can lead to different conclusions. This is an often‐discussed paradox in psychology and education. Aims. The reasons why these approaches can lead to different conclusions, the assumptions that each approach makes and how the approaches relate to group allocation, are discussed Methods. Three sets of simulations are reported that investigate the relationships among effect size, group allocation, measurement error and Lord's paradox. Conclusions. Recommendations are given that stress careful examination of the research questions, sampling and allocation of participants and graphing the data. ANCOVA is appropriate when allocation is based on the initial scores, t test can be appropriate if allocation is associated non‐causally with the initial scores, but often neither approach provides adequate results.     

Reaction time and intelligence: Comparing associations based on two response modes

People who score highly on intelligence tests also tend to have faster and less variable reaction times. Effect size estimates for the reaction time–intelligence association are larger in samples that are more representative of the population. However, such samples have often been tested on a reaction time device that requires reading a number and processing its association with a specific response location (Cox, Huppert, & Whichelow, 1993). Here, we use this device and another reaction time device (Dykiert et al., 2010) that is similar, except that the responses require less processing; subjects simply press a button that is adjacent to the stimulus light. We focus on the possibility that lights as stimuli require less higher-order cognitive engagement than numbers, and then test whether parameters from these two tasks are highly correlated and similarly associated with age and higher cognitive abilities. Both tasks measured simple and choice reaction times and their intra-individual variation across trials. The parameters of the two tasks were very highly correlated and parameters from both tasks were similarly associated with age, social factors, and differences in higher cognitive abilities. The respective choice reaction time parameters from either task accounted for much of the age- and higher cognitive ability-associations of the other task's parameters. These findings are important in establishing that the effect sizes of higher cognitive ability associations with processing speed measures may be found when the processing demands are minimal.     

Helping Teams to Help Themselves: Comparing two Team‐Led Debriefing Methods

Team‐based structures have become more widely used in organizations. Therefore, it is important for team members to perform well in their current team and to build skills and enthusiasm for working on future teams. This study examined team debriefing, an intervention in which team members reflect on recent experiences to prepare for subsequent tasks. Prior researchers have shown that facilitated team debriefs work, but they have not examined how to enable teams to conduct their own debriefs or studied how debriefs affect individual level outcomes. Therefore, we compared 2 team‐led debriefing techniques: (a) an unguided debrief and (b) a guided debrief designed to incorporate lessons learned from prior debriefs. We collected data from 174 business students who were members of 35 teams from 9 sections of a Strategic Management course. Class sections were randomly assigned to one of the debriefing conditions, and teams completed 4 business cases over 10 weeks. A multilevel design was employed and a multistage model building approach was used to test the hypotheses using hierarchical linear modeling techniques. Results of this cluster randomized, quasi‐experimental design suggest that the team‐led guided debrief intervention resulted in superior team processes as compared to the unguided debriefing method. Team processes, in turn, related significantly to greater team performance and increased individual readiness for teamwork and enthusiasm for teaming. Implications for future research and practice are discussed.     

The Role of Self‐focused Attention and Negative Self‐thought in Interview Anxiety: A test of two interventions

Job interview anxiety is an unpleasant experience for many candidates that can cause them significant distress in the days leading up to the interview. As a result, many candidates are motivated to overcome their feelings of anxiety, however, few empirical studies have examined strategies aimed at lowering nervous jitters. This study looked at the relation between interview anxiety and ‘self‐focused attention’ (the tendency to focus on oneself during the interview), and also negative self‐thoughts during the interview. We tested two training interventions that are grounded in the social anxiety literature, positive imagery (fostering positive self‐images), and field perspective taking (focusing attention externally), which were designed to reduce self‐focused attention and negative thought. Both interventions decreased interview anxiety and increased interview self‐efficacy, but did not affect interview performance scores.     

Attachment‐based intervention for substance‐using mothers: A preliminary test of the proposed mechanisms of change

Although randomized controlled trials examining the efficacy of attachment‐based interventions have been increasing in recent years, adequate measurement of treatment integrity, integrity–outcome associations, and mechanisms of change has been rare. The aim of this investigation was to conduct a rigorous test of proposed mechanisms of change in the Mothers and Toddlers Program (MTP) treatment model, a 12‐session, attachment‐based individual therapy for substance‐using mothers of children birth to 3 years of age. The MTP aims to improve maternal reflective functioning (RF) and representation quality (RQ) to bring about second‐order change in maternal caregiving behavior. Following guidelines from M.K. Nock ( 2007 ), it was hypothesized that (a) therapist adherence to unique MTP treatment components would uniquely predict improvement in RF and RQ and that (b) improvement in RF and RQ would function as unique mechanisms of change (when compared with other potential mechanisms—reduction in depression and increase in abstinence from drug use) in the improvement of caregiving behavior. Findings supported each hypothesis, confirming the proposed mechanisms of the treatment model. However, improvement in maternal depression also uniquely predicted improvement in caregiving behavior. Results underscore the potential value of attachment‐based parenting interventions for improving mother–child relations and the importance of providing these interventions in clinic settings where mothers have access to comprehensive care (e.g., psychiatric services).     

A meta‐mood model of rumination and depression: Preliminary test in a non‐clinical population

Depressive rumination and trait meta‐mood (emotional attention, emotional clarity and emotional repair) have been suggested as vulnerability factors leading to depression, but less is known about the associations among them. In this study, we examined the relationships between trait meta‐mood, rumination and depressive symptomatology. Using structural equation analysis in a large sample of a non‐clinical population we found a preliminary test of the role of trait meta‐mood dimensions in rumination and depressive symptomatology. Results indicated that attention to feelings has two pathways in its relation with rumination and depressive mood. On the one hand, emotional attention was associated with emotional clarity, and emotional clarity with emotional repair, which was related to lower depressive symptomatology, in part, by reducing rumination. On the other hand, emotional attention was directly associated with ruminative thoughts which, in turn, were related to higher depressive mood. Findings are discussed in terms of the implications of beliefs about emotions in the treatment of depression.     

The role of women's self‐injury support‐groups: a grounded theory

Research evidence suggests that services are struggling to adequately address the increasing incidence of self‐injury and the needs of women who self‐injure, while national self‐injury support‐groups across the UK appear to be growing in number. Despite their reported value, evidence regarding the role of self‐injury support‐groups in women's management of their self‐injury is lacking although government policy and official guidelines are advocating the incorporation of support‐groups into self‐injury services. Seven semi‐structured interviews were conducted and analysed using Grounded Theory to investigate the role of three UK self‐injury support‐groups in women's management of self‐injury and associated difficulties. Empowerment‐as‐process emerged as the core theme of self‐injury support‐groups, mediated through experiences of belonging, sharing, autonomy, positive feeling and change. Findings are discussed in relation to relevant theory and research, followed by critical evaluation and implications of the study. Copyright © 2006 John Wiley & Sons, Ltd.     

The Validity of Conscientiousness for Predicting Job Performance: A meta‐analytic test of two hypotheses

This study examined two hypotheses regarding the moderating effects of job characteristics on the validity of personality. Using meta‐analytic techniques, the authors explored the extent to which the structural characteristics and cognitive ability requirements of jobs influence the role of conscientiousness in predicting performance. The results suggest that conscientiousness is a stronger predictor of performance in jobs that are highly routinized, and a weaker predictor of performance in jobs with high levels of cognitive ability requirements. Implications for theory and future research are discussed.     

Comparing Personality Test Formats and Warnings: Effects on criterion‐related validity and test‐taker reactions

The potential for applicant response distortion on personality measures remains a major concern in high‐stakes testing situations. Many approaches to understanding response distortion are too transparent (e.g., instructed faking studies) – or are too subtle (e.g., correlations with social desirability measures as indices of faking). Recent research reveals more promising approaches in two methods: using forced‐choice (FC) personality test items and warning against faking. The present study examined effects of these two methods on criterion‐related validity and test‐taker reactions. Results supported incremental validity for an FC and Likert‐scale measure in warning and no‐warning conditions, above and beyond cognitive ability. No clear differences emerged between the FC vs Likert measures or warning vs no‐warning conditions in terms of validity. However, some evidence suggested that FC measures and warnings may produce negative test‐taker reactions. We conclude with implications for implementation in selection settings.     

Surface‐ and deep‐level dissimilarity effects on social integration and individual effectiveness related outcomes in work groups: A meta‐analytic integration

Prior research linking demographic (e.g., age, ethnicity/race, gender, and tenure) and underlying psychological (e.g., personality, attitudes, and values) dissimilarity variables to individual group member's work‐related outcomes produced mixed and contradictory results. To account for these findings, this study develops a contingency framework and tests it using meta‐analytic and structural equation modelling techniques. In line with this framework, results showed different effects of surface‐level (i.e., demographic) dissimilarity and deep‐level (i.e., underlying psychological) dissimilarity on social integration, and ultimately on individual effectiveness related outcomes (i.e., turnover, task, and contextual performance). Specifically, surface‐level dissimilarity had a negative effect on social integration under low but not under high team interdependence. In return, social integration fully mediated the negative relationship between surface‐level dissimilarity and individual effectiveness related outcomes under low interdependence. In contrast, deep‐level dissimilarity had a negative effect on social integration, which was stronger under high and weaker under low team interdependence. Contrary to our predictions, social integration did not mediate the negative relationship between deep‐level dissimilarity and individual effectiveness related outcomes but suppressed positive direct effects of deep‐level dissimilarity on individual effectiveness related outcomes. Possible explanations for these counterintuitive findings are discussed.     

The effect of supervisory feedback,self‐recording,and graphic feedback on trainer behavior during one‐to‐one training

The effectiveness of supervisory feedback, self‐recording, and graphic feedback on trainer behavior during one‐to‐one training sessions was assessed with three trainers, and three students with mental retardation. Supervisory feedback consisted of a supervisor interrupting the course of the training if an error occurred, administering appraisal when accurate trainer behavior occurred, and prompting the trainer to avoid errors. Following this, self‐recording and graphic feedback were in effect. During the latter condition, the trainer was instructed to record her own behavior, to graph the data following each training session, and to set a goal to increase her performance. Data were collected in a quasi non‐concurrent multiple baseline design across dyads of trainers and students. The results showed a statistically significant increase of accurate trainer behavior during supervisory feedback, which was maintained during the condition of self‐recording and graphic feedback. Maintenance of trainer behavior was recorded during follow‐up. The trainers rated supervisory feedback as more acceptable than self‐recording and graphic feedback. Copyright © 2005 John Wiley & Sons, Ltd.     

Work‐group and organizational support: A test of distinct dimensions

Using data from 467 members of a large firm in the United States, this paper found that perceived work‐group support is a distinct construct from perceived organizational support. To reinforce the uniqueness of the constructs, the work‐group and organizational support constructs exhibited meaningful, differential relationships with six of eight variables reflecting different levels of exchange relationships and commitments. The implications of these findings are discussed.     

Stereotype Threat: A Meta‐Analysis Comparing African Americans to Hispanic Americans1

Stereotype threat theory posits an explanation for cognitive underperformance in groups based on social stereotypes. When stereotypes are negatively related to a cognitive task, awareness of this relationship leads to decreased performance on that task; however, this underperformance can be reduced by actively dismissing the stereotype or disguising the nature of the task. This meta‐analysis examined the effects of stereotype threat nullification among African Americans and Hispanic Americans. There was a moderate improvement in scores for both African American and Hispanic Americans' performance when stereotype threat was nullified (d = 0.52). However, there were no differences between African Americans and Hispanic Americans or between the experimental methods used to create stereotype threats in terms of their effects on the outcomes.     

Health‐adjusted neuropsychological test norms based on 463 older Swedish car drivers

There is a need for improved normative information in particular for older persons. The present study provides neuropsychological test norms on seven cognitive tests used in a sample representing the general older driving population, when uncontrolled and controlled for physical health. A group of 463 healthy Swedish car drivers, aged 65 to 84 years, participated in a medical and neuropsychological examination. The latter included tests of visual scanning, mental shifting, visual spatial function, memory, reaction time, selective attention, and simultaneous capacity. Hierarchical regression analyses demonstrated that, when uncontrolled for health, old age was associated with significant impairment on all seven tests. Education was associated with a significant advantage for all tests except most reaction time subtests. Women outperformed men on selective attention. Controlling for health did not consistently change the associations with education, but generally weakened those with age, indicating rises in normative scores of up to 0.36 SD (residual). In terms of variance explained, impaired health predicted on average 2.5%, age 2.9%, education 2.1% and gender 0.1%. It was concluded (1) that individual regression‐based predictions of expected values have the advantage of allowing control for the impact of health on normative scores in addition to the adjustment for various demographic and performance‐related variables and (2) that health‐adjusted norms have the potential to classify functional status more accurately, to the extent that these norms diverge from norms uncontrolled for physical health.     

A test of foreign language acquisition: paired‐association learning

This experiment investigated college student difficulties with foreign language acquisition. We developed a word‐sound, paired‐associates learning test that discriminated 92% of the control participants and 95% of the experimental participants. The results are interpreted in terms of an associative model of foreign language learning disability. We discuss how to integrate the test into a larger diagnostic battery for predicting the facility with which a person will be able to learn a foreign language. Copyright © 2002 John Wiley & Sons, Ltd.     

An alternative to Cohen's standardized mean difference effect size: a robust parameter and confidence interval in the two independent groups case

The authors argue that a robust version of Cohen's effect size constructed by replacing population means with 20% trimmed means and the population standard deviation with the square root of a 20% Winsorized variance is a better measure of population separation than is Cohen's effect size. The authors investigated coverage probability for confidence intervals for the new effect size measure. The confidence intervals were constructed by using the noncentral t distribution and the percentile bootstrap. Over the range of distributions and effect sizes investigated in the study, coverage probability was better for the percentile bootstrap confidence interval.