Testing a series of causal propositions relating time in child care to children’s externalizing behavior.

[Correction Notice: An erratum for this article was reported in Vol 46(2) of Developmental Psychology (see record 2010-03975-013). On the first page of the article “Testing a Series of Causal Propositions Relating Time in Child Care to Children’s Externalizing Behavior,” by Kathleen McCartney, Margaret Burchinal, Alison Clarke- Stewart, Kristen L. Bub, Margaret T. Owen, Jay Belsky, and the NICHD Early Child Care Research Network (Developmental Psychology, 2010, Vol. 46, No. 1, pp. 1–17), author Alison Clarke- Stewart’s name was misspelled as Aliso Clarke-Stewart. In addition, the e-mail address listed for the corresponding author Kathleen McCartney is incorrect. The correct e-mail address is: kathleen_mccartney@gse.harvard.edu. The online versions of this article have been corrected.] Prior research has documented associations between hours in child care and children’s externalizing behavior. A series of longitudinal analyses were conducted to address 5 propositions, each testing the hypothesis that child care hours causes externalizing behavior. Data from the National Institute of Child Health and Human Development Early Child Care Research Network (NICHD) Study of Early Child Care and Youth Development were used in this investigation because they include repeated measures of child care experiences, externalizing behavior, and family characteristics. There were 3 main findings. First, the evidence linking child care hours with externalizing behavior was equivocal in that results varied across model specifications. Second, the association between child care hours and externalizing behavior was not due to a child effect. Third, child care quality and proportion of time spent with a large group of peers moderated the effects of child care hours on externalizing behavior. The number of hours spent in child care was more strongly related to externalizing behavior when children were in low-quality child care and when children spent a greater proportion of time with a large group of peers. The magnitude of associations between child care hours and externalizing behavior was modest. Implications are that parents and policymakers must take into account that externalizing behavior is predicted from a constellation of variables in multiple contexts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Child-care effect sizes for the NICHD Study of Early Child Care and Youth Development.

This report summarizes findings from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development as effect sizes for exclusive maternal care and--for children in child care--type, quality, and quantity of care. Children (n = 1,261) were recruited at birth and assessed at 15, 24, 36, and 54 months. Exclusive maternal care did not predict child outcomes, but multiple features of child-care experience were modestly to moderately predictive. Higher quality child care was related to advanced cognitive, language, and preacademic outcomes at every age and better socioemotional and peer outcomes at some ages. More child-care hours predicted more behavior problems and conflict, according to care providers. More center-care time was related to higher cognitive and language scores and more problem and fewer prosocial behaviors, according to care providers. Child-care effect sizes are discussed from 3 perspectives: (a) absolute effect sizes, reflecting established guidelines; (b) relative effect sizes, comparing child-care and parenting effects; and (c) possible individual and collective implications for the large numbers of children experiencing child care. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Does attention-deficit/hyperactivity disorder have a dimensional latent structure? A taxometric analysis.

An understanding of the latent structure of attention-deficit/hyperactivity disorder (ADHD) is essential for developing causal models of this disorder. Although some researchers have presumed that ADHD is dimensional and others have assumed that it is taxonic, there has been relatively little research directly examining the latent structure of ADHD. The authors conducted a set of taxometric analyses using data from the NICHD Study of Early Child Care and Youth Development (ns between 667 and 1,078). The results revealed a dimensional latent structure across a variety of different analyses and sets of indicators for inattention, hyperactivity/impulsivity, and ADHD. Furthermore, analyses of correlations with associated features indicated that dimensional models demonstrated stronger validity coefficients with these criterion measures than dichotomous models. These findings jibe with recent research on the genetic basis of ADHD and with contemporary models of ADHD. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Correction to Gross et al. (2003).

Reports an error in the original article by D. Gross et al (Journal of Consulting and Clinical Psychology, 2003[Apr], Vol 71[2], pp. 261-278). The article was mistitled. The correct title is "Parent Training with Multi-Ethnic Families of Toddlers in Day Care in Low-Income Urban Communities". (The following abstract of the article originally appeared in record 2003-02091-006.) The authors tested a 12-week parent training program with parents (n=208) and teachers (n=77) of 2-3-year-olds in day care centers serving low-income families of color in Chicago. Eleven centers were randomly assigned to 1 of 4 conditions: (a) parent and teacher training (PT + TT), (b) parent training (PT), (c) teacher training (TT), and (d) waiting list control (C). After controlling for parent stress, PT and PT + TT parents reported higher self-efficacy and less coercive discipline and were observed to have more positive behaviors than C and TT parents. Among toddlers in high-risk behavior problem groups, toddlers in the experimental conditions showed greater improvement than controls. Most effects were retained 1 year later. Benefits were greatest when parents directly received training. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to Forrest et al. (2008).

Reports an error in "Psychology trainees with competence problems: From individual to ecological conceptualizations" by Linda Forrest, Nancy S. Elman and David S. Shen Miller (Training and Education in Professional Psychology, 2008[Nov], Vol 2[4], 183-192). The order of authorship was printed incorrectly, both in the issue Table of Contents and in the article. The correct order of authorship for this article is: Linda Forrest, Nancy S. Elman, and David S. Shen Miller. (The following abstract of the original article appeared in record 2008-17021-001.) Problems with professional competence or impairment in psychology have been viewed almost exclusively as residing within the individual trainee or psychologist, with limited attention to the contexts in which such difficulties are embedded. The authors propose an ecological perspective (Bronfenbrenner, 1979, 1989, 1995) to capture the influence of multiple factors that affect trainee development and provide a stronger base from which to conceptualize and address problems of professional competence. The authors describe Bronfenbrenner's ecological model and use it as a framework to understand professional competence problems, recommend best practices for prevention and intervention, and suggest future research directions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to Rydell et al. (2010).

Reports an error in "The effect of negative performance stereotypes on learning" by Robert J. Rydell, Michael T. Rydell and Kathryn L. Boucher (Journal of Personality and Social Psychology, 2010[Dec], Vol 99[6], 883-896). There is an error in the first paragraph of the Results section on page 886. The third sentence in this paragraph reads “As predicted, the stereotype threat manipulation did not affect women's learning of mathematical rules presented before the instructions, F (1, 57) = 0.68, p = .41, ηp2 = .01; however, women in the stereotype threat condition learned fewer mathematical rules presented after the instructions than did women in the control condition, F (1, 57) = 3.96, p = .05, ηp2 = .07.” Given the data, the second part of the sentence should have read “however, women in the stereotype threat condition showed a non-significant trend towards learning fewer mathematical rules presented after the instructions than did women in the control condition, F (1, 57) = 3.56, p = .064, ηp2 = .06.” (The following abstract of the original article appeared in record 2010-20715-001.) Stereotype threat (ST) research has focused exclusively on how negative group stereotypes reduce performance. The present work examines if pejorative stereotypes about women in math inhibit their ability to learn the mathematical rules and operations necessary to solve math problems. In Experiment 1, women experiencing ST had difficulty encoding math-related information into memory and, therefore, learned fewer mathematical rules and showed poorer math performance than did controls. In Experiment 2, women experiencing ST while learning modular arithmetic (MA) performed more poorly than did controls on easy MA problems; this effect was due to reduced learning of the mathematical operations underlying MA. In Experiment 3, ST reduced women's, but not men's, ability to learn abstract mathematical rules and to transfer these rules to a second, isomorphic task. This work provides the first evidence that negative stereotypes about women in math reduce their level of mathematical learning and demonstrates that reduced learning due to stereotype threat can lead to poorer performance in negatively stereotyped domains. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Correction to Guillot et al. (2010).

Reports an error in Effects of alcohol on tests of executive functioning in men and women: A dose response examination by Casey R. Guillot, Jennifer R. Fanning, Joshua S. Bullock, Michael S. McCloskey and Mitchell E. Berman (Experimental and Clinical Psychopharmacology, 2010[Oct], Vol 18[5], 409-417). This article contained errors in the text. These errors are explained and corrected in the correction. (The following abstract of the original article appeared in record 2010-21046-003.) Alcohol has been shown to affect performance on tasks associated with executive functioning. However, studies in this area have generally been limited to a single dose or gender or have used small sample sizes. The purpose of this study was to provide a more nuanced and systematic examination of alcohol's effects on commonly used tests of executive functioning at multiple dosages in both men and women. Research volunteers (91 women and 94 men) were randomly assigned to one of four drink conditions (alcohol doses associated with target blood alcohol concentrations of .000%, .050%, .075%, and .100%). Participants then completed three tasks comprising two domains of executive functioning: two set shifting tasks, the Trail Making Test and a computerized version of the Wisconsin Card Sorting Task, and a response inhibition task, the GoStop Impulsivity Paradigm. Impaired performance on set shifting tasks was found at the .100% and .075% dosages, but alcohol intoxication did not impair performance on the GoStop. No gender effects emerged. Thus, alcohol negatively affects set shifting at moderately high levels of intoxication in both men and women, likely attributable to alcohol's interference with prefrontal cortex function. Although it is well established that alcohol negatively affects response inhibition as measured by auditory stop-signal tasks, alcohol does not appear to exert a negative effect on response inhibition as measured by the GoStop, a visual stop-signal task. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Correction to Fehr et al. (2010).

Reports an error in The road to forgiveness: A meta-analytic synthesis of its situational and dispositional correlates by Ryan Fehr, Michele J. Gelfand and Monisha Nag (Psychological Bulletin, 2010[Sep], Vol 136[5], 894-914). In Table 2, weighted population correlations and associated standard errors and confidence intervals are incorrectly reported. In Table 3, weighted population correlations and associated confidence intervals are incorrectly reported, as well as the Q statistic for trait forgiveness. Corrected data are presented. The authors note that substantive interpretations of the results are not affected by the corrections. The median absolute value correction for the weighted population correlations in both tables is r = .01. (The following abstract of the original article appeared in record 2010-17510-010.) Forgiveness has received widespread attention among psychologists from social, personality, clinical, developmental, and organizational perspectives alike. Despite great progress, the forgiveness literature has witnessed few attempts at empirical integration. Toward this end, we meta-analyze results from 175 studies and 26,006 participants to examine the correlates of interpersonal forgiveness (i.e., forgiveness of a single offender by a single victim). A tripartite forgiveness typology is proposed, encompassing victims' (a) cognitions, (b) affect, and (c) constraints following offense, with each consisting of situational and dispositional components. We tested hypotheses with respect to 22 distinct constructs, as correlates of forgiveness, that have been measured across different fields within psychology. We also evaluated key sample and study characteristics, including gender, age, time, and methodology as main effects and moderators. Results highlight the multifaceted nature of forgiveness. Variables with particularly notable effects include intent (r? = ?.49), state empathy (r? = .51), apology (r? = .42), and state anger (r? = ?.41). Consistent with previous theory, situational constructs are shown to account for greater variance in forgiveness than victim dispositions, although within-category differences are considerable. Sample and study characteristics yielded negligible effects on forgiveness, despite previous theorizing to the contrary: The effect of gender was nonsignificant (r? = .01), and the effect of age was negligible (r? = .06). Preliminary evidence suggests that methodology may exhibit some moderating effects. Scenario methodologies led to enhanced effects for cognitions; recall methodologies led to enhanced effects for affect. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Correction to Mikels et al. (2010).

Reports an error in "Following your heart or your head: Focusing on emotions versus information differentially influences the decisions of younger and older adults" by Joseph A. Mikels, Corinna E. L?ckenhoff, Sam J. Maglio, Laura L. Carstensen, Mary K. Goldstein and Alan Garber (Journal of Experimental Psychology: Applied, 2010[Mar], Vol 16[1], 87-95). The wrong author order was listed. The correct order is presented in the erratum. (The following abstract of the original article appeared in record 2010-06152-007.) Research on aging has indicated that whereas deliberative cognitive processes decline with age, emotional processes are relatively spared. To examine the implications of these divergent trajectories in the context of health care choices, we investigated whether instructional manipulations emphasizing a focus on feelings or details would have differential effects on decision quality among younger and older adults. We presented 60 younger and 60 older adults with health care choices that required them to hold in mind and consider multiple pieces of information. Instructional manipulations in the emotion-focus condition asked participants to focus on their emotional reactions to the options, report their feelings about the options, and then make a choice. In the information-focus condition, participants were instructed to focus on the specific attributes, report the details about the options, and then make a choice. In a control condition, no directives were given. Manipulation checks indicated that the instructions were successful in eliciting different modes of processing. Decision quality data indicate that younger adults performed better in the information-focus than in the control condition whereas older adults performed better in the emotion-focus and control conditions than in the information-focus condition. Findings support and extend extant theorizing on aging and decision making as well as suggest that interventions to improve decision-making quality should take the age of the decision maker into account. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to diamond et al. (2010).

Reports an error in "Ongoing traumatic stress response (OTSR) in Sderot, Israel" by Gary M. Diamond, Joshua D. Lipsitz, Zvi Fajerman and Omit Rozenblat (Professional Psychology: Research and Practice, 2010[Feb], Vol 41[1], 19-25). In the article “Ongoing Traumatic Stress Response (OTSR) in Sderot, Israel,” by Diamond, Lipsitz, Fajerman and Rozenblat (Professional Psychology: Research and Practice, 2010, Vol. 41, No. 1., pp. 19–25), due to a production error, the last author’s name was misspelled in the byline and the author note. The correct spelling is Ornit Rozenblat. (The following abstract of the original article appeared in record 2010-02467-003.) In Sderot, a small city in southern Israel, seven years of continuous missile attacks have led to dramatic increases in treatment seeking for anxiety symptoms. For some clients, the clinical picture is consistent with a diagnosis of post traumatic stress disorder (PTSD). For other clients, however, the onset and constellation of symptoms are less typical of PTSD. In these cases, anxiety symptoms seem to evolve gradually and be associated with ongoing, daily stress about imminent attacks, rather than with a discrete, past traumatic event. Much of their avoidance behavior is reality based. They report hyperarousal, severe distress, and loss of control during and immediately following actual missile attacks. However, they are less likely to exhibit reexperiencing symptoms. Furthermore, in contrast to the typical presentation of PTSD, their symptoms tend to diminish dramatically or completely resolve when they are no longer within harm’s way. We suggest that this clinical presentation may be best understood as an ongoing traumatic stress response (OTSR), rather than PTSD or PTSD symptoms. We consider diagnostic features which discriminate between these two phenomena as well as implications for treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to Shin et al. (2010).

Reports an error in A review of contemporary ideomotor theory by Yun Kyoung Shin, Robert W. Proctor and E. J. Capaldi (Psychological Bulletin, 943-974). In the Online First Publication of the article “A Review of Contemporary Ideomotor Theory” by Yun Kyoung Shin, Robert W. Proctor, and E. J. Capaldi (Psychological Bulletin, posted September 6, 2010, doi: 10.1037/a0020541), the title of the article was incorrectly listed as “A Review of Contemporary Idiomatic Theory.” All versions of this article have been corrected. (The following abstract of the original article appeared in record 2010-18185-001.) A framework for action planning, called ideomotor theory, suggests that actions are represented by their perceivable effects. Thus, any activation of the effect image, either endogenously or exogenously, will trigger the corresponding action. We review contemporary studies relating to ideomotor theory in which researchers have investigated various manipulations of action effects and how those effects acquire discriminative control over the actions. Evidence indicates that the knowledge about the relation between response and effect is still a critical component even when other factors, such as stimulus–response or response–response relations, are controlled. When consistent tone effects are provided after responses are made, performance in serial-reaction tasks is better than when the effects are random. Methodology in which acquisition and test stages are used with choice–reaction tasks shows that an action is automatically associated with its effect bilaterally and that anticipation of the effect facilitates action. Ideomotor phenomena include stimulus–response compatibility, in which the perceptual feature of the stimulus activates its corresponding action code when the stimulus itself resembles the effect codes. For this reason, other stimulus-driven action facilitation such as ideomotor action and imitation are treated as ideomotor phenomena and are reviewed. Ideomotor theory also implies that ongoing action affects perception of concurrent events, a topic which we review briefly. Issues concerning ideomotor theory are identified and evaluated. We categorize the range of ideomotor explanations into several groups by whether intermediate steps are assumed to complete sensorimotor transformation or not and by whether a general theoretical framework or a more restricted one is provided by the account. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to Castonguay et al. (2010).

Reports an error in Psychotherapists, researchers, or both? A qualitative analysis of psychotherapists' experiences in a practice research network by Louis G. Castonguay, Dana L. Nelson, Mary A. Boutselis, Nancy R. Chiswick, Diana D. Damer, Neal A. Hemmelstein, Jeffrey S. Jackson, Marolyn Morford, Stephen A. Ragusea, J. Gowen Roper, Catherine Spayd, Tara Weiszer and Thomas D. Borkovec (Psychotherapy: Theory, Research & Practice, 2010[Sep], Vol 47[3], 345-354). The first sentence of the second paragraph of the author note on page 345 was incorrect. The corrected sentence is as follows: “The study was conducted with funding provided by the Pennsylvania Psychological Association and the Committee for the Advancement of Professional Practice of the American Psychological Association”. (The following abstract of the original article appeared in record 2010-20923-008.) This paper describes the experiences of psychotherapists who, as part of a practice research network (PRN), collaborated with researchers in designing and conducting a psychotherapy study within their own clinical practices. A qualitative analysis of interviews conducted with these psychotherapists led to the delineation of several benefits (e.g., learning information that improved their work with clients and feeling that they were contributing to research that would be useful for psychotherapists) and difficulties for them and their clients (e.g., time and effort required to integrate research protocol into routine clinical practice) that psychotherapists associated with their participation in the PRN. Also identified were a number of strategies used by psychotherapists to address obstacles that they encountered, as well as general recommendations for future PRN studies. As a whole, the experiences of these psychotherapists are likely to provide valuable lessons for the survival and growth of what is viewed by many as a promising pathway for building a stronger bridge between practice and research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to Estrada-Hollenbeck et al. (2010).

Reports an error in Toward a model of social influence that explains minority student integration into the scientific community by Mica Estrada-Hollenbeck, Anna Woodcock, Paul R. Hernandez and P. Wesley Schultz (Journal of Educational Psychology, np). The name of the author Mica Estrada-Hollenbeck should have read Mica Estrada. All versions of this article have been corrected. (The following abstract of the original article appeared in record 2010-22529-001.) Students from several ethnic minority groups are underrepresented in the sciences, indicating that minority students more frequently drop out of the scientific career path than nonminority students. Viewed from a perspective of social influence, this pattern suggests that minority students do not integrate into the scientific community at the same rate as nonminority students. Kelman (1958, 2006) described a tripartite integration model of social influence by which a person orients to a social system. To test whether this model predicts integration into the scientific community, we conducted analyses of data from a national panel of minority science students. A structural equation model framework showed that self-efficacy (operationalized to be consistent with Kelman's rule orientation) predicted student intentions to pursue a scientific career. However, when identification as a scientist and internalization of values were added to the model, self-efficacy became a poorer predictor of intention. Additional mediation analyses supported the conclusion that while having scientific self-efficacy is important, identifying with and endorsing the values of the social system reflect a deeper integration and more durable motivation to persist as a scientist. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Correction to Berry et al. (2010).

Reports an error in Can “pure” implicit memory be isolated? A test of a single-system model of recognition and repetition priming by Christopher J. Berry, David R. Shanks, Selina Li, Luke Sheridan Rains and Richard N. A. Henson (Canadian Journal of Experimental Psychology/Revue canadienne de psychologie expérimentale, 2010[Dec], Vol 64[4], 241-255). In the article there was an error in Equation B2 in Appendix B. (The following abstract of the original article appeared in record 2010-26226-002.) Implicit memory is widely regarded as an unconscious form of memory. However, evidence for what is arguably a defining characteristic of implicit memory—that its contents are not accessible to awareness—has remained elusive. Such a finding of “pure” implicit memory would constitute evidence against a single-system model of recognition and priming that predicts that priming will not occur in the (true) absence of recognition. In three experiments, using a rapid serial visual presentation procedure at encoding, we tested this prediction by attempting to replicate some previous studies that claimed to obtain pure implicit memory. We found no evidence of priming in the absence of recognition; instead, priming and recognition were associated across experiments: when priming was absent, recognition was also absent (Experiments 1 and 2), and when priming was reliably greater than chance, recognition was similarly greater than chance (Experiment 3). The results are consistent with the prediction of a single-system model, which was fit to the data from all the experiments. The results are also consistent with the notion that the memory driving priming is accessible to awareness. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Correction to Aarons et al. (2010).

Reports an error in "Psychometric properties and U.S. National norms of the Evidence-Based Practice Attitude Scale (EBPAS)" by Gregory A. Aarons, Charles Glisson, Kimberly Hoagwood, Kelly Kelleher, John Landsverk and Guy Cafri (Psychological Assessment, 2010[Jun], Vol 22[2], 356-365). There were three errors in Table 1 on p. 360. In the last row, the row label should be “Overall EBPAS mean,” M = 2.73, and SD = 0.49. The revised Table 1 appears in the erratum. (The following abstract of the original article appeared in record 2010-10892-016.) The Evidence-Based Practice Attitude Scale (EBPAS) assesses mental health and social service provider attitudes toward adopting evidence-based practices. Scores on the EBPAS derive from 4 subscales (i.e., Appeal, Requirements, Openness, and Divergence) as well as the total scale, and preliminary studies have linked EBPAS scores to clinic structure and policies, organizational culture and climate, and first-level leadership. EBPAS scores are also related to service provider characteristics, including age, education level, and level of professional development. The present study examined the factor structure, reliability, and norms of EBPAS scores in a sample of 1,089 mental health service providers from a nationwide sample drawn from 100 service institutions in 26 states in the United States. The study also examined associations of provider demographic characteristics with EBPAS subscale and total scores. Confirmatory factor analysis supported a second-order factor model, and reliability coefficients for the subscales ranged from .91 to .67 (total scale = .74). The study establishes national norms for the EBPAS so that comparisons can be drawn for U.S. local as well as international studies of attitudes toward evidence-based practices. The results suggest that the factor structure and reliability are likely generalizable to a variety of service provider contexts and different service settings and that the EBPAS subscales are associated with provider characteristics. Directions for future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to Schulz et al. (2005).

Reports an error in the original article by Kurt P. Schulz, Cheuk Y. Tang, Jin Fan, David J. Marks, Angeles M. Cheung, Jeffrey H. Newcorn, and Jeffrey M. Halperin ((Neuropsychology, 2005, Vol. 19, No. 3, pp. 390-402). Some side headings in Tables 2 and 3 were incorrect, and the corrected tables appear here. (The following abstract of this article originally appeared in record 2005-05103-013). "The authors examined inhibitory control processes in 8 adolescents diagnosed with attention-deficit/ hyperactivity disorder (ADHD) during childhood and in 8 adolescent control participants using functional MRI with the Stimulus and Response Conflict Tasks (K. W. Nassauer & J. M. Halperin, 2003). No group differences in performance were evident on measures of interference control and/or response competition created by location and direction stimuli. However, the ADHD group demonstrated significantly greater activation of the left ventrolateral prefrontal cortex during interference control as well as greater activation of the left anterior cingulate cortex, right ventrolateral prefrontal cortex, and left basal ganglia during the dual task of interference control and response competition. The magnitude of the prefrontal and basal ganglia activation was positively correlated with severity of ADHD. Response competition alone did not yield group differences in activation." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to Venter et al. (2002).

Reports an error in the original article by A. Venter et al (Psychological Methods, 2002[Jun], Vol No. 7[2], 194-209. On page 202, there were 2 errors. Appendix B correctly shows that Equation 17 and 18 should read as indicated here. (The following abstract of this article originally appeared in record 2002-13431-003.) Adding a pretest as a covariate to a randomized posttest-only design increases statistical power, as does the addition of intermediate time points to a randomized pretest-posttest design. Although typically 5 waves of data are required in this instance to produce meaningful gains in power, a 3-wave intensive design allows the evaluation of the straight-line growth model and may reduce the effect of missing data. The authors identify the statistically most powerful method of data analysis in the 3-wave intensive design. If straight-line growth is assumed, the pretest-posttest slope must assume fairly extreme values for the intermediate time point to increase power beyond the standard analysis of covariance on the posttest with the pretest as covariate, ignoring the intermediate time point. (PsycINFO Database Record (c) 2010 APA, all rights reserved)