Validity generalization work over the past 25 years has called into question the veracity of the assumption that validity is situationally specific. Recent theoretical and methodological work has suggested that validity coefficients may be transportable even if true validity is not a constant. Most transportability work is based on the assumption that the distribution of rho ( ρi ) is normal, yet, no empirical evidence exists to support this assumption. The present study used a competing model approach in which a new procedure for assessing transportability was compared with two more commonly used methods. Empirical Bayes estimation (Brannick, 2001; Brannick & Hall, 2003) was evaluated alongside both the Schmidt-Hunter multiplicative model (Hunter & Schmidt, 1990) and a corrected Hedges-Vevea (see Hall & Brannick, 2002; Hedges & Vevea, 1998) model. The purpose of the present study was two-fold. The first part of the study compared the accuracy of estimates of the mean, standard deviation, and the lower bound of 90 and 99 percent credibility intervals computed from the three different methods across 32 simulated conditions. The mean, variance, and shape of the distribution varied across the simulated conditions. The second part of the study involved comparing results of analyses of the three methods based on previously published validity coefficients. The second part of the study was used to show whether choice of method for determining whether transportability is warranted matters in practice. Results of the simulation analyses suggest that the Schmidt-Hunter method is superior to the other methods even when the distribution of true validity parameters violates the assumption of normality. Results of analyses conducted on real data show trends consistent with those evident in the analyses of the simulated data. Conclusions regarding transportability, however, did not change as a function of method used for any of the real data sets. Limitations of the present study as well as recommendations for practice and future research are provided.

Floods are major disturbance events for riverine ecosystems, directly and indirectly impacting organisms and their habitat. In this study I investigated the role of riverine floods and flow alteration in regulating aquatic macroinvertebrate population and community structure. I examined this problem using a variety of methods: a meta-analytic review of primary studies from the literature, a mathematical model synthesizing population and flood ecology, a multi-year experimental flood program in an arid-land river, and a field investigation of flood recovery behaviors in a charismatic larval odonate. I found that floods significantly reduced invertebrate abundance in the short term, but had varied effects across particular study sites, microhabitats, and taxonomic groups. I determined that both resistant and resilient capabilities are important to persistence of invertebrate populations after disturbance events, and that these traits may act in a binary fashion. Recovery over time of invertebrate populations may be partially due to "hidden resistance" of spatially displaced individuals in side-channels, benthic substrate, and vegetation or wood. Some invertebrates adapted to flood-prone rivers may possess behavioral adaptations for returning to the main-channel of the river after flood events. This dissertation contributes to riverine disturbance ecology and provides information useful to prediction and management of ecosystem flows in rivers. / Graduation date: 2012

Teams are pervasive in organizations and provide an important contribution to organizational productivity. Since Hackman's (1987) seminal work, the team research focus has shifted from describing teams to outlining how researchers might use points of leverage, such as team design, to increase team effectiveness. There has been a wealth of research on team design variables that relate to team effectiveness. However, more than 15 years later, the team design literature remains fragmented and is inconsistent, and conclusions regarding optimal team design are difficult to make. The present study sought to unify the team design research by proposing a conceptual model and testing hypothesized relationships between specified design variables and team effectiveness using meta-analytic techniques. Specifically, the objectives of this study were to: (a) identify team design variables over which researchers and practitioners have some degree of control, (b) summarize the literature related to each of these variables, (c) hypothesize how each of the design variables are related to team effectiveness, (d) assess the relationship between these variables and team effectiveness using meta-analysis, (e) assess the influence of specified moderator variables (e.g., study setting, team tenure) on the team design variable/team effectiveness relationships, (f) make theoretically- and empirically-based recommendations for the design of effective teams, and (g) highlight areas in need of additional research. Results indicated that several team design variables show promise as a means of increasing team effectiveness. The strength of the team composition variable/team performance relationships was dependent on the study setting (lab or field); however, the study setting had considerable overlap with the type of team assessed (intellectual or physical). For lab studies (intellectual teams), team general mental ability (GMA) and task-relevant expertise were strong predictors of team performance, while team personality variables were unrelated to team performance. In field studies (physical teams), team agreeableness and conscientiousness had stronger relationships with team performance than team GMA and team task-relevant expertise. Team task design variables (e.g., task significance) had consistent, positive relationships with team performance, and several team structure variables (e.g., degree of self- management) were also related to team performance.

A variety of statistical models have been developed to examine longitudinal stability and change of individual differences. Kenny and Zautra’s (1995) trait-state-error (TSE) model models stability as a function of stable variance that does not change (trait), moderately stable variance that changes over time (state), and error variance. Applications of this model have been limited to panel studies with repeated observations of the same individual. The present study developed a non-linear regression model to apply the TSE model to retest correlations from different samples. This model was used to compare the stability of measures of personality traits, affective well-being (AWB), cognitive well-being (CWB), and self-esteem. After correcting for differences in reliability, age, gender, and scale length, the amount of trait (vs. state) variance was similar across constructs. Stability of the state component was highest for AWB and CWB, suggesting that situational influences have most enduring effects on these two constructs.

Objective to systematically review randomized trials that compared methotrexate (MTX) monotherapy to MTX in combination with other non-biologic disease-modifying anti-rheumatic Drugs (DMARD) and to compare the performances of PubMed versus MEDLINE (Ovid®) and EMBASE. Methods We performed a systematic review of randomized trials comparing MTX alone and MTX in combination with other non-biologic DMARDs. Heterogeneity was investigated and explored. The performances of Pubmed and MEDLINE were evaluated. The EMBASE unique trials were identified and investigated. Results A total of 19 trials were included and grouped by the type of patients randomized. Trials in DMARD naive patients showed no significant advantage of the MTX combination versus monotherapy. The recall was 85% vs. 90% for Ovid and PubMed, respectively, while the precision and number-needed-to read of Ovid and Pubmed were comparable. Only 23% of trials were EMBASE unique trials Conclusions In DMARD naive patients, the balance of efficacy/toxicity favours MTX monotherapy.

BACKGROUND: MRI is increasingly being used for rectal cancer staging. The purpose of this study was to summarize published evidence to determine the accuracy of MRI for T-category, lymph node (LN) metastases, and circumferential resection margin (CRM) involvement in rectal cancer. METHODS: Sensitivity, specificity, and diagnostic odds ratios (DOR) were estimated using hierarchical summary receiver operating characteristics modeling and bivariate random effects modeling. RESULTS: MRI was more specific for CRM (94%, 95%CI 88-97) than for T-category (75%, 95%CI 68-80) and LN’s (71%, 95%CI 59-81) but was more sensitive for T-category (87%, 95%CI 81-92) than for CRM (77%, 95%CI 57-90) and LN’s (77%, 95%CI 69-84). DOR was higher for CRM (56.1, 95%CI 15.3-205.8) than for LN’s (8.3, 95%CI 4.6-14.7) and T-category (20.4, 95%CI 11.1-37.3). CONCLUSIONS: MRI has good accuracy for both CRM and T-category and should be considered for preoperative rectal cancer staging. In contrast, LN assessment is poor on MRI.

BACKGROUND: MRI is increasingly being used for rectal cancer staging. The purpose of this study was to summarize published evidence to determine the accuracy of MRI for T-category, lymph node (LN) metastases, and circumferential resection margin (CRM) involvement in rectal cancer. METHODS: Sensitivity, specificity, and diagnostic odds ratios (DOR) were estimated using hierarchical summary receiver operating characteristics modeling and bivariate random effects modeling. RESULTS: MRI was more specific for CRM (94%, 95%CI 88-97) than for T-category (75%, 95%CI 68-80) and LN’s (71%, 95%CI 59-81) but was more sensitive for T-category (87%, 95%CI 81-92) than for CRM (77%, 95%CI 57-90) and LN’s (77%, 95%CI 69-84). DOR was higher for CRM (56.1, 95%CI 15.3-205.8) than for LN’s (8.3, 95%CI 4.6-14.7) and T-category (20.4, 95%CI 11.1-37.3). CONCLUSIONS: MRI has good accuracy for both CRM and T-category and should be considered for preoperative rectal cancer staging. In contrast, LN assessment is poor on MRI.

Children’s risk for overweight and obesity is particularly high in rural areas of the United States. Many health, psychosocial, and economic consequences are associated with childhood overweight and obesity, which concerns health researchers and professionals. But how and why might rural children be more at risk for being overweight and obese? This dissertation investigates childhood overweight and obesity in rural settings through three separate studies. First, a systematic literature review was conducted to identify determinants and mechanisms of childhood obesity-related behaviors that are specific to rural locations. The findings from the review show that lack of health resources and poverty within the rural environment may impact children’s social environment and individual factors. However, results are inconclusive and there continues to be a lack of studies focusing on linking environmental influence with individual factors. Second, a meta-analysis of current research evidence was conducted to assess the efficacy of rural interventions designed to reduce childhood overweight and obesity. Results showed that interventions have been efficacious yet modest, with a mean effect size of 0.18. Moderating variables were also examined. Mean intervention effect size was moderated by children’s age and intervention duration. Last, secondary data were used to examine the association between rural food stores and availability and affordability of fresh fruits and vegetables. A multilevel analytical approach was used to determine if rural location was associated with availability and affordability of fresh fruits and vegetables. After controlling for other variables, results showed that rural location was not associated with fruit and vegetable availability and affordability. The findings from this dissertation suggest that the area of rural childhood overweight and obesity remains understudied. More research is needed in order to understand the mechanisms of social ecological influences on diet, physical activity, and childhood overweight and obesity. This area of research, however, is rife with opportunities for public health education and promotion. Public health educators can help promote and advocate for environmental conditions that support healthy lifestyles.

A variety of statistical models have been developed to examine longitudinal stability and change of individual differences. Kenny and Zautra’s (1995) trait-state-error (TSE) model models stability as a function of stable variance that does not change (trait), moderately stable variance that changes over time (state), and error variance. Applications of this model have been limited to panel studies with repeated observations of the same individual. The present study developed a non-linear regression model to apply the TSE model to retest correlations from different samples. This model was used to compare the stability of measures of personality traits, affective well-being (AWB), cognitive well-being (CWB), and self-esteem. After correcting for differences in reliability, age, gender, and scale length, the amount of trait (vs. state) variance was similar across constructs. Stability of the state component was highest for AWB and CWB, suggesting that situational influences have most enduring effects on these two constructs.

Objective to systematically review randomized trials that compared methotrexate (MTX) monotherapy to MTX in combination with other non-biologic disease-modifying anti-rheumatic Drugs (DMARD) and to compare the performances of PubMed versus MEDLINE (Ovid®) and EMBASE. Methods We performed a systematic review of randomized trials comparing MTX alone and MTX in combination with other non-biologic DMARDs. Heterogeneity was investigated and explored. The performances of Pubmed and MEDLINE were evaluated. The EMBASE unique trials were identified and investigated. Results A total of 19 trials were included and grouped by the type of patients randomized. Trials in DMARD naive patients showed no significant advantage of the MTX combination versus monotherapy. The recall was 85% vs. 90% for Ovid and PubMed, respectively, while the precision and number-needed-to read of Ovid and Pubmed were comparable. Only 23% of trials were EMBASE unique trials Conclusions In DMARD naive patients, the balance of efficacy/toxicity favours MTX monotherapy.