Design and analysis of group-randomized trials: a review of recent methodological developments

We review recent developments in the design and analysis of group-randomized trials (GRTs). Regarding design, we summarize developments in estimates of intraclass correlation, power analysis, matched designs, designs involving one group per condition, and designs in which individuals are randomized to receive treatments in groups. Regarding analysis, we summarize developments in marginal and conditional models, the sandwich estimator, model-based estimators, binary data, survival analysis, randomization tests, survey methods, latent variable methods and nonlinear mixed models, time series methods, global tests for multiple endpoints, mediation effects, missing data, trial reporting, and software. We encourage investigators who conduct GRTs to become familiar with these developments and to collaborate with methodologists who can strengthen the design and analysis of their trials.

The placebo effect: dissolving the expectancy versus conditioning debate

The authors review the literature on the 2 main models of the placebo effect: expectancy theory and classical conditioning. A path is suggested to dissolving the theoretical impasse that has long plagued this issue. The key is to make a clear distinction between 2 questions: What factors shape placebo effects? and What learning mediates the placebo effect? The reviewed literature suggests that classical conditioning procedures are one shaping factor but that verbal information can also shape placebo effects. The literature also suggests that conditioning procedures and other sources of information sometimes shape conscious expectancies and that these expectancies mediate some placebo effects; however, in other cases conditioning procedures appear to shape placebo effects that are not mediated by conscious cognition.

Assumptions and consequences of treating providers in therapy studies as fixed versus random effects: reply to Crits-Christoph, Tu, and Gallop (2003) and Serlin, Wampold, and Levin (2003)

In their comments on the authors' article, R. C. Serlin, B. E. Wampold, and J. R. Levin and P. Crits-Christoph, X. Tu, and R. Gallop took issue with the authors' suggestion to evaluate therapy studies with nested providers with a fixed model approach. In this rejoinder, the authors' comment on Serlin et al's critique by showing that their arguments do not apply, are based on misconceptions about the purpose and nature of statistical inference, or are based on flawed reasoning. The authors also comment on Crits-Christoph et al's critique by showing that the proposed approach is very similar to, but less inclusive than, their own suggestion.

Therapists as fixed versus random effects-some statistical and conceptual issues: a comment on Siemer and Joormann (2003)

The authors disagree with M. Siemer and J. Joormann's assertion that therapist should be a fixed effect in psychotherapy treatment outcome studies. If treatment is properly standardized, therapist effects can be examined in preliminary tests and the therapist term deleted from analyses if such differences approach zero. If therapist effects are anticipated and either cannot be minimized through standardization or are specifically of interest because of the nature of the research question, the study has to be planned with adequate statistical power for including therapist as a random term. Simulation studies conducted by Siemer and Joormann confounded bias due to small sample size and inconsistent estimates.

Is it prudent to administer all items for each Child Behavior Checklist cross-informant syndrome? Evaluating the psychometric properties of the Youth Self-Report dimensions with confirmatory factor analysis and item response theory

Through surveying of children in 10 nations with parent, teacher, and Youth Self-Report (YSR) forms of the Child Behavior Checklist (CBCL), cross-informant syndromes (CISs) were derived and cross-validated by sample-dependent methodology. Generalizing CBCL syndromes and norms to nations excluded from its normative sample is problematic. This study used confirmatory factor analyses (CFAs) to test factor model fit for CISs on the YSR responses of 625 Jamaican children ages 11 to 18 years. Item response theory (IRT), a sample-independent methodology, was used to estimate the psychometric properties of individual items on each dimension. CFAs indicated poor to moderate model-to-data fit. Across all syndromes, IRT analyses revealed that more than 3/4 of the cross-informant items yielded little information. Eliminating such items could be cost effective in terms of administration time yet improve the measures discrimination across syndrome severity levels.

Power and measures of effect size in analysis of variance with fixed versus random nested factors

Ignoring a nested factor can influence the validity of statistical decisions about treatment effectiveness. Previous discussions have centered on consequences of ignoring nested factors versus treating them as random factors on Type I errors and measures of effect size (B. E. Wampold & R. C. Serlin). The authors (a) discuss circumstances under which the treatment of nested provider effects as fixed as opposed to random is appropriate; (b) present 2 formulas for the correct estimation of effect sizes when nested factors are fixed; (c) present the results of Monte Carlo simulations of the consequences of treating providers as fixed versus random on effect size estimates, Type I error rates, and power; and (d) discuss implications of mistaken considerations of provider effects for the study of differential treatment effects in psychotherapy research.

Qualitative and quantitative analyses of historical data

Although the typical study in psychology involves the quantitative analysis of contemporary research participants, occasionally psychologists will study historical persons or events. Moreover, these historical data may be analyzed using either qualitative or quantitative techniques. After giving examples from the subdisciplines of cognitive, developmental, differential, abnormal, and social psychology, the distinctive methodological features of this approach are outlined. These include both data collection (sampling, unit definition, etc.) and data analysis (both qualitative and quantitative). The discussion then turns to the advantages and disadvantages of this research method. The article closes by presenting the reasons why (a) psychologists will probably continue to use historical data and (b) quantitative analyses may eventually replace qualitative analyses in such applications.

Temporal stability of the intrinsic motivation inventory

To examine the temporal stability of the Intrinsic Motivation Inventory a Greek version was administered to 144 undergraduate students after an endurance field test. The same procedure was repeated one week later. Factor analysis followed by varimax rotation showed that three factors (Perceived Competence, Interest/enjoyment, and Effort/importance) explained 65.26% of the total variance. Computed intraclass correlation coefficients (ICC) were .61 for the Perceived Competence subscale, .86 for the Interest/enjoyment, .60 for the Effort/importance, and .70 for the overall scale. The results, however, were modified when the sample was divided in two groups. The first represented small changes in perceived competence between the first and the second measurement, while the second one represented large changes between the two measurements. Recalculated intraclass correlation coefficients for individuals whose Perceived Competence score remained relatively stable yield a high value (.92), whereas individuals whose Perceived Competence changed yield an extremely low value (.60). It was concluded that the Intrinsic Motivation Inventory provides a temporally stable measure, given that perceived competence has not been markedly changed.

Convergent and discriminant validity of trait and source effects in ADHD-inattention and hyperactivity/impulsivity measures across a 3-month interval

Confirmatory factor analysis was used to model a multitrait (ADHD-inattention and hyperactivity/ impulsivity) by multisource (teachers and parents) design across a 3-month interval in a sample of 360 Australian elementary school children. The purpose was to evaluate the convergent and discriminant validity of the ADHD-inattention (IN) and hyperactivity/impulsivity (H/I) measures. Although similar traits and similar sources showed stronger correlations across time than dissimilar traits and dissimilar sources, the amount of source variance in the ADHD-IN and ADHD-H/I measures was substantial and consistent across the interval (M = 59%; range = 35-84%). This large amount of source variance raises the possibility that the correlations of the IN and H/I rating scales with other constructs (e.g., social competence, conduct problems) represent mostly source rather than trait effects. Multitrait by multisource analyses provide a means to answer this question and further advance understanding of ADHD.

Reliability of a computerized assessment of psychomotor performance and its sensitivity to alcohol-induced impairment

Two experiments examined a new computerized pursuit rotor task that measured psychomotor performance. Exp. 1 examined the acquisition and reliability of performance of 25 adults who performed the task on two sessions separated by a 2-wk. interval. Exp. 2 was a placebo-controlled test of task sensitivity to the performance-impairing effects of a 0.65 g/kg dose of alcohol. Exp. 1 showed that participants' performance was reliable over time. Exp. 2 showed that alcohol-impaired performance compared with placebo. The task could be useful for evaluating performance-impairing effects of other CNS depressant drugs, as well as complementing assessment batteries for research and instruction in studies of motor learning and human performance.

The role of acceptance and job control in mental health, job satisfaction, and work performance

Acceptance, the willingness to experience thoughts, feelings, and physiological sensations without having to control them or let them determine one's actions, is a major individual determinant of mental health and behavioral effectiveness in a more recent theory of psychopathology. This 2-wave panel study examined the ability of acceptance also to explain mental health, job satisfaction, and performance in the work domain. The authors hypothesized that acceptance would predict these 3 outcomes 1 year later in a sample of customer service center workers in the United Kingdom (N = 412). Results indicated that acceptance predicted mental health and an objective measure of performance over and above job control, negative affectivity, and locus of control. These beneficial effects of having more job control were enhanced when people had higher levels of acceptance. The authors discuss the theoretical and practical relevance of this individual characteristic to occupational health and performance.

Perceived partner critical and avoidant behaviors as predictors of anxious and depressive symptoms among mothers of children undergoing hemopaietic stem cell transplantation

This prospective study examined the role of perceived partner criticism and avoidance in the anxiety and depressive symptoms of 148 mothers of children undergoing hemopaietic stem cell transplantation (HSCT). The roles of indicators of transplantation risk and posttransplantation medical course were also examined. Perceived partner criticism (e.g., criticizing coping efforts) and perceived partner avoidance (e.g., changing the topic), objective indicators of transplantation risk, and anxiety and depressive symptoms were assessed at the time of HSCT and again 3 and 6 months later. Growth curve modeling analyses indicated that perceived partner criticism was associated with higher average depressive symptoms. However, perceived partner criticism did not predict changes in mother's anxiety. Contrary to predictions, perceived partner avoidance was associated with decreases in maternal anxiety.

A path model of risk factors for intimate partner violence among couples in the United States

The present study was designed to identify the impact of drinking problems, impulsivity, and a history of childhood physical abuse on both male-to-female (MFIPV) and female-to-male intimate partner violence (FMIPV). The data were collected in 1995 from a representative national sample of couples living in the contiguous 48 states. Using a multistage probability sampling design, face-to-face interviews were conducted in respondent' homes, privately with each member of 1, 635 couples. A complex path model building on earlier work was tested for African American, Hispanic, and White couples separately. Multiple-group path analysis demonstrated that impulsivity, alcohol problems, and childhood physical abuse were differentially associated with reports of MFIPV and FMIPV as a function of ethnicity. This study suggests that a history of being physically harmed by parental figures during childhood, impulsivity, and drinking problems are all risk factors for intimate partner violence in the general household population in the United States.

The feasibility and effectiveness of an expressive writing intervention for rheumatoid arthritis via home-based videotaped instructions

BACKGROUND

Expressive emotional writing has demonstrated efficacy for improving health status in a wide variety of healthy persons and recently in patients with chronic disease.

PURPOSE

This study was a randomized, controlled effectiveness trial with 4 arms: 2 active treatment writing groups, 1 inactive writing group, and 1 attention control group. It represents the first attempt to translate the expressive writing intervention into a low-cost, community-based intervention in the form of a videotaped program.

METHODS

Feasibility of the approach and patient adherence were examined in a community rheumatology practice with rheumatoid arthritis patients (N = 373).

RESULTS

The videotape format was able to convey the intervention instructions accurately and produced the expected and differential ratings of stressfulness and emotional provocation across the 3 writing programs. Seventy-nine percent of eligible patients agreed to take the program home; 49% of these patients reported that they followed the protocol. Physician Disease Activity Rating and the Physical Component Summary of the SF36v2 Health Survey were assessed pre and post program.

CONCLUSIONS

Intent-to-treat analyses found no effect of the treatment. Pretreatment differences among the protocol-adherent patients complicated treatment outcome interpretation. The standard writing instructions did not yield an effect; a modified set of instructions to extract meaning from the traumatic event yielded equivocal results. Contrasts between efficacy and effectiveness trials and the challenge of achieving significant outcomes in effectiveness trials are discussed.

The relationship between the use of kinaesthetic imagery and different visual imagery perspectives

In two studies, we examined the strength of relationship between internal and external visual imagery with kinaesthetic imagery. In Study 1, 56 participants completed the Vividness of Movement Imagery Questionnaire and the Movement Imagery Questionnaire. Pearson's product-moment correlations failed to reveal a significant correlation between external visual imagery and kinaesthetic imagery. However, the correlation between internal visual imagery and kinaesthetic imagery approached significance. In Study 2, the instructional set of the Vividness of Movement Imagery Questionnaire was changed to make the participant the 'agent' of the external visual perspective images rather than somebody else. Sixty-four participants completed the two questionnaires. The results indicated a significant correlation between external visual imagery and kinaesthetic imagery (r = 0.60, P < 0.01). However, the correlation between internal visual imagery and kinaesthetic imagery was non-significant (r = 0.23, P > 0.01). The results are discussed in relation to who is the agent of the image and the processes that may underlie kinaesthetic imagery. The implications for researchers trying to establish the functional, behavioural and neurological differences within, and across, imagery modalities are considered.

Earthquake beliefs and adoption of seismic hazard adjustments

This study investigated the prevalence of both accurate and erroneous earthquake-related beliefs among a sample of Southern California college students and the relationship between their endorsement of earthquake beliefs and adoption of seismic hazard adjustments. In addition, the study examined the effects of an experimental earthquake education program and the impact of need for cognition on this program. The data revealed a significant degree of agreement with earthquake myths, a generally low level of correlation between earthquake beliefs and the level of hazard adjustments, and a significant effect of hazard information on the endorsement of accurate earthquake beliefs and increases in hazard adjustment. Compared with the "Earthquake Facts (Only)" format, an "Earthquake Myths versus Facts" format was slightly more useful for dispelling erroneous beliefs. Further, there was a tendency for those who were high in need for cognition to have higher levels of hazard adjustment. Finally, there was weak support for the hypothesis that those who were low in need for cognition would develop more accurate earthquake beliefs and higher levels of hazard adjustment in the "Earthquake Myths versus Facts" information condition.

Human Research and Data Collection via the Internet

Advantages and disadvantages of Web and lab research are reviewed. Via the World Wide Web, one can efficiently recruit large, heterogeneous samples quickly, recruit specialized samples (people with rare characteristics), and standardize procedures, making studies easy to replicate. Alternative programming techniques (procedures for data collection) are compared, including client-side as opposed to server-side programming. Web studies have methodological problems; for example, higher rates of drop out and of repeated participation. Web studies must be thoroughly analyzed and tested before launching on-line. Many studies compared data obtained in Web versus lab. These two methods usually reach the same conclusions; however, there are significant differences between college students tested in the lab and people recruited and tested via the Internet. Reasons that Web researchers are enthusiastic about the potential of the new methods are discussed.

A structural analysis of working memory and related cognitive skills in young children

The aim of this study was to investigate the functional organisation of working memory and related cognitive abilities in young children. A sample of 633 children aged between 4 and 6 years were tested on measures of verbal short-term memory, complex memory span, sentence repetition, phonological awareness, and nonverbal ability. The measurement model that provided the best fit of the data incorporates constructs that correspond to the central executive, phonological loop, and episodic buffer subcomponents of working memory, plus distinct but associated constructs associated with phonological awareness and nonverbal ability.

Early childcare and physical aggression: differentiating social selection and social causation

BACKGROUND

Some research findings have suggested that group day-care may be associated with an increased risk for physical aggression.

METHODS

Cross-sectional maternal questionnaire data from a representative sample of 3431 Canadian 2- to 3-year-olds were used to compare rates of physical aggression shown by children looked after by their own mothers and those attending group day-care. A family risk index (using occupational level, maternal education, size of sibship, and family functioning) was created to test whether any difference in physical aggression might reflect social selection rather than social causation.

RESULTS

Aggression was significantly more common in children looked after by their own mothers than in those attending group day-care. Strong social selection associated with family risk was found, not only in the sample as a whole, but even within the high-risk subsample. However, after taking social selection into account, physical aggression was significantly more common in children from high-risk families looked after by their own parents. No such difference was evident in the majority (84%) of children from low-risk families.

CONCLUSION

Insofar as there are any risks for physical aggression associated with homecare they apply only to high-risk families.

Comparing the developmental trajectories of marijuana use of African American and Caucasian adolescents: patterns, antecedents, and consequences

Adolescent marijuana use has tripled recently, and the once-noted race gap between African American and Caucasian adolescents in marijuana use appears to have disappeared. Yet, relatively little research has examined marijuana use among African American adolescents. In this study, we examined developmental trajectories of marijuana use among Caucasian and African American adolescents to identify whether and when differences in marijuana use appear and whether the precursors and outcomes associated with these developmental trajectories differ by race. Findings indicate that both the developmental patterns and outcomes associated with marijuana use are different for African American and Caucasian adolescents. Early-onset Caucasian and mid-onset African American adolescents experienced the greatest number of negative outcomes later in life associated with their marijuana use, suggesting that groups to target for intervention may vary by race.

Attitudes of American and Israeli Staff Toward People With Intellectual Disabilities

We compared the inclusion-related attitudes of community agency staff in the United States and Israel. Samples of 147 (United States) and 74 (Israel) staff members were assessed with the Community Living Attitudes Scale (CLAS). Results showed that higher educational levels, regardless of nation, were associated with higher Empowerment scores, lower Exclusion scores, lower Sheltering scores, and higher Similarity scores. Empowerment attitudes were strongly related to differences in the agencies in which individuals were employed. Controlling for age, education, and agency, we found that staff in the United States had higher Empowerment scores than did Israeli staff. Israeli staff had higher Sheltering and Similarity scores and marginally higher Exclusion scores than did the United States staff.

Absence Culture

Drawing from Nicholson and Johns (1985) typology of absence culture (N = 460 from 43 work groups), we found that greater similarity in union membership status between co-workers was associated with a lowering of a member’s absence culture, as was a more harmonious union-management (UM) climate. In addition, greater similarity in union membership was related to a lowered absence culture when the UM climate was perceived to be positive. The theoretical and practical implications of these findings for understanding the social context in which the absence culture of union members is engendered are discussed.

Exploring the dimensionality of the Originality subscale of the Kirton Adaption-Innovation Inventory

The Kirton Adaption-Innovation Inventory, which is a widely used measure of innovative (as opposed to adaptive) cognitive individual style, is believed to have three dimensions: Sufficiency of Originality, Efficiency, and Rule/Group Conformity. Several studies have raised concerns regarding its construct validity, specifically with respect to the Sufficiency of Originality subscale. Within this subscale, exploratory factor analysis identified two distinct subdimensions, Idea Generation and Preference for Change. In this study, we used a sample of 356 household participants (with an average age of 56 yr., average income of 39,700 dollars, and average of 15 yr. of education) from the Arkansas Household Research Panel. We then employed Bollen and Grandjean's approach based on confirmatory factor analysis to assess whether there are actually two distinct subdimensions instead of one. Our study shows that within the Sufficiency of Originality subscale, there are indeed two distinct subdimensions, Idea Generation and Preference for Change. Further analyses indicate that dropping double-loaded items identified through exploratory factor analysis significantly improves the fit statistics. Also, allowing correlated errors for the measurement items that belong to the same subdimension can also significantly improve the overall fit of the model based on chi-square statistics.

Is caregiving hazardous to one's physical health? A meta-analysis

Caring for a family member with dementia is generally regarded as a chronically stressful process, with potentially negative physical health consequences. However, no quantitative analysis has been conducted on this literature. The authors combined the results of 23 studies to compare the physical health of caregivers with demographically similar noncaregivers. When examined across 11 health categories, caregivers exhibited a slightly greater risk for health problems than did noncaregivers. However, sex and the health category assessed moderated this relationship. Stronger relationships occurred with stress hormones, antibodies, and global reported health. The authors argue that a theoretical model is needed that relates caregiver stressors to illness and proffers moderating roles for vulnerabilities and resources and mediating roles for psychosocial distress and health behaviors.

The Relationship Between Expertise and Evaluative Extremity: The Moderating Role of Experts' Task Characteristics

Past research has yielded contradictory results with regard to the relationship between expertise and evaluative extremity. The authors suggest that this apparent contradiction is due to the task characteristics of the expert activity. The primary task of certain experts is to formulate overall (configural) judgments and to generate clear, unambiguous answers. These experts tend to give relatively extreme evaluations. Other experts generally communicate the implications of the different choice alternatives and explain featural aspects of the stimuli. These experts are characterized by relatively moderate evaluations. The research reported in this article shows that experts whose expert activity involves configural judgments tend to make more extreme evaluations than experts who generally provide others with featural explanations. It also demonstrates that experts' task characteristics affect the way they store stimulus-relevant attributes in memory.

Family Income and Its Relation to Preschool Children's Adjustment for Families in the NICHD Study of Early Child Care

The current study examines relations of mean-level estimates, linear changes, and instability in income and family processes to child outcomes and addresses whether income, through its impact on family functioning, matters more for children living in poverty. Temporal changes and instability in family processes, but not income, predicted children's adjustment. Cross-sectional mediational analyses indicated that for families living at the poverty threshold, family processes fully mediated the effect of average income over the study period on social behavior but only partially mediated its effect on cognitive-linguistic development. The strength of these associations diminished as average income exceeded the poverty threshold. That is, income had a greater impact on the family functioning and development of poor children than of nonpoor children.

Categorical versus dimensional approaches to diagnosis: methodological challenges

The arguments pitting categorical versus dimensional approaches to psychiatric diagnosis have been long ongoing with little sign of imminent resolution. We argue that categorical and dimensional approaches are fundamentally equivalent, but that one or other approach is more appropriate depending on the clinical circumstances and research questions being addressed. This paper aims to demonstrate (a) how these two approaches necessarily interdigitate, (b) to clarify the conditions under which one should utilize one approach over the other, and (c) to alert psychiatric clinicians and researchers to issues in the methodology literature that might facilitate their considerations. Using an example from the Infant Health and Development Program (IHDP), we illustrate the importance of using dimensional approaches for hypothesis testing, identify the problems with power and with interpretation that arise from employing a categorical approach, and underscore the importance of identifying the appropriate cutpoints when a categorical approach is necessitated. We argue that failure to utilize the correct approach under the appropriate circumstances can result in impaired clinical and research decision-making.

Dissociative symptoms are related to endorsement of vague trauma items

In current psychiatric literature, the received view is that dissociative symptoms originate from aversive childhood events. To a large extent, this view is based on cross-sectional studies that do not rule out a scenario in which dissociative tendencies contribute to self-reports of childhood trauma. In two studies, we tested one particular implication of this scenario, namely, that dissociative symptoms are related to endorsement of vague rather than specific items about childhood trauma. In study 1 (N = 43) and study 2 (N = 127), nonclinical participants completed standard measures of dissociation, childhood trauma, and fantasy proneness. We performed correlational and regression analyses on the data. Fantasy proneness and responses to broad trauma items, but not responses to factual trauma items predicted dissociation levels. This pattern of findings shows that the link between trauma and dissociation is considerably more complex than is often assumed. As well, it suggests that at least in nonclinical samples, dissociative symptoms may breed endorsement of vague trauma items.

Testing Hypotheses About the Person-Response Function in Person-Fit Analysis

The person-response function (PRF) relates the probability of an individual's correct answer to the difficulty of items measuring the same latent trait. Local deviations of the observed PRF from the expected PRF indicate person misfit. We discuss two new approaches to investigate person fit. The first approach uses kernel smoothing to estimate continuous PRF estimates. Graphical displays of PRFs were used to localize and diagnose misfit. The second approach approximates the PRF by a logistic regression model. Hypothesis tests on the regression parameters were used to detect certain types of misfit. A simulation study was conducted to investigate the Type I error rates and the detection rates of the regression approach.

Nonparametric analysis of ordinal data in designed factorial experiments

ABSTRACT Plant disease severity often is assessed using an ordinal rating scale rather than a continuous scale of measurement. Although such data usually should be analyzed with nonparametric methods, and not with the typical parametric techniques (such as analysis of variance), limitations in the statistical methodology available had meant that experimental designs generally could not be more complicated than a one-way layout. Very recent advancements in the theoretical formulation of hypotheses and associated test statistics within a nonparametric framework, together with development of software for implementing the methods, have made it possible for plant pathologists to analyze properly ordinal data from more complicated designs using nonparametric techniques. In this paper, we illustrate the nonparametric analysis of ordinal data obtained from two-way factorial designs, including a repeated measures design, and show how to quantify the effects of experimental factors on ratings through estimated relative marginal effects.

A Functional Approach to the Assessment of Self-Mutilative Behavior

This study applied a functional approach to the assessment of self-mutilative behavior (SMB) among adolescent psychiatric inpatients. On the basis of past conceptualizations of different forms of self-injurious behavior, the authors hypothesized that SMB is performed because of the automatically reinforcing (i.e., reinforced by oneself; e.g., emotion regulation) and/or socially reinforcing (i.e., reinforced by others; e.g., attention, avoidance-escape) properties associated with such behaviors. Data were collected from 108 adolescent psychiatric inpatients referred for self-injurious thoughts or behaviors. Adolescents reported engaging in SMB frequently, using multiple methods, and having an early age of onset. Moreover, the results supported the structural validity and reliability of the hypothesized functional model of SMB. Most adolescents engaged in SMB for automatic reinforcement, although a sizable portion endorsed social reinforcement functions as well. These findings have direct implications for the understanding, assessment, and treatment of SMB.

A Comparison of the Reliabilities of Four Types of Difference Scores for Five Cognitive Assessment Batteries

Summary: In recent years, studies have been conducted comparing the reliability of simple difference scores to differences computed via reliable component analysis (RCA). For the five cognitive assessment batteries examined here, RCA difference scores have been superior to simple difference scores in this regard. In the present study, the five cognitive assessment batteries are considered again, including a comparison of two alternative methods of difference score construction, the residualized and base-free difference methods, in order to determine if RCA outperforms the other methods as well. Results indicated that the RCA difference scores were more reliable in 68/70 comparisons between the four methods. When difference scores are a central part of test interpretation, clinicians should use the RCA scoring method because of the high reliability of the difference scores.

Social Motives and Strategic Misrepresentation in Social Decision Making

In 4 experiments, the authors studied the influence of social motives on deception and strategic misrepresentation. In a newly developed information provision game, individuals faced a decision maker whose decision would affect both own and other's outcomes. By withholding information or by giving (in)accurate information about payoffs, participants could try to influence other's decision making. Less accurate and more inaccurate information was given when the decision maker was competitive rather than cooperative (Experiment 1), especially when participants had a prosocial rather than selfish value orientation (Experiments 3 and 4). Accurate information was withheld because of fear of exploitation and greed, and inaccurate information was given because of greed (Experiment 2). Finally, participants engaged in strategic misrepresentation that may trick competitive others into damaging their own and increasing the participant's outcomes.

How can statistical approaches enhance transdisciplinary study of drug misuse prevention?

Application of statistical techniques in transdisciplinary research includes statistical model selection and model specification. This paper presents statistical models used in drug misuse prevention research. The historical roots of these models are discussed to illustrate the numerous disciplines from which different techniques originated. Single and multilevel approaches are described to illustrate methods of synthesizing perspectives from different scientific arenas. Using single-level approaches in transdisciplinary research, these models can easily incorporate broader theoretical considerations and more integrated hypotheses by representing each discipline with a set of variables. Simultaneous testing of every set of variables obtained from different disciplines may provide more comparable results to identify critical factors associated with substance-use behavior. Using multilevel approaches, more powerful syntheses across disciplines can be achieved by representing each discipline at a different level.

More on the Fragility of Performance: Choking Under Pressure in Mathematical Problem Solving

In 3 experiments, the authors examined mathematical problem solving performance under pressure. In Experiment 1, pressure harmed performance on only unpracticed problems with heavy working memory demands. In Experiment 2, such high-demand problems were practiced until their answers were directly retrieved from memory. This eliminated choking under pressure. Experiment 3 dissociated practice on particular problems from practice on the solution algorithm by imposing a high-pressure test on problems practiced 1, 2, or 50 times each. Infrequently practiced high-demand problems were still performed poorly under pressure, whereas problems practiced 50 times each were not. These findings support distraction theories of choking in math, which contrasts with considerable evidence for explicit monitoring theories of choking in sensorimotor skills. This contrast suggests a skill taxonomy based on real-time control structures.

A Revised Methodology for Research on Metamemory: Pre-judgment Recall And Monitoring (PRAM)

A revised methodology is described for research on metacognitive monitoring, especially judgments of learning (JOLs), to investigate psychological processing that previously has been only hypothetical and unobservable. During data collection a new stage of recall occurs just prior to the JOL, so that during data analysis the items can be partitioned into subcategories to measure the degree of JOL accuracy in ways that are more analytic than was previously possible. A weighted-average combinatorial rule allows the component measures of JOL accuracy to be combined into the usual overall measure of metacognitive accuracy. An example using the revised methodology offers a new explanation for the delayed-JOL effect, in which delayed JOLs are more accurate than immediate JOLs for predicting recall.

Dissociation and violence: a review of the literature

Violent acts are sometimes committed by people who do not normally appear violent or aggressive. This simple observation and others have led some to speculate about a relationship between dissociation and violence. However, no systematic review of the literature has so far been published. To address this gap, studies assessing the prevalence of dissociation among violent individuals, and violence among highly dissociative persons, are reviewed. Possible links between dissociation and violent behavior are explored. It is concluded that dissociation predicts violence in a wide range of populations and may be crucial to an understanding of violent behavior. There is a clear need, however, for large scale, well-designed studies using reliable structured instruments in a number of areas reviewed. Recommendations for clinical applications include the routine screening of offenders for dissociative disorders and adequate consideration of dissociation and dissociative disorders in the development and implementation of violence treatment and prevention programs.

Toward an Alternative Representation for Disentangling Age-Associated Differences in General and Specific Cognitive Abilities

Much of cognitive aging research concerns whether age-associated differences in various cognitive performances can be accounted for by general explanatory constructs or whether several specific processes are involved. Structural equation models have been proposed to disentangle general and specific age-associated differences in cognitive performance. This article demonstrates that existing methods that employ stepwise procedures run the risk of biasing results toward general resource accounts. An alternative model representation (i.e., the nested factor model) is proposed that affords simultaneous estimation of general and specific effects and is applied to data from the Berlin Aging Study. Using the nested factor model allowed the authors to detect that specific group factors explained 25% of the age-associated variance in addition to the general factor.