Chondra M Lockwood's research while affiliated with Oregon Health and Science University and other places

Publications (16)

Article
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To evaluate the effects of a research-tested, team-based health promotion and wellness program combined with digital technologies and implemented in a diverse worksite setting among hospital, clinic, and university employees. A prospective cohort study of employees completing biometrics and questionnaires before and after the initial 12-session wel...
Article
Mediation analysis is a newer statistical tool that is becoming more prominent in nutrition research. Its use provides insight into the relationship among variables in a potential causal chain. For intervention studies, it can define the influence of different programmatic components and, in doing so, allows investigators to identify and refine a p...
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Adolescence and emerging adulthood are critical windows for establishing life-long behaviors. We assessed long-term outcomes of a prospective randomized harm reduction/health promotion program for female high school athletes. The intervention's immediate beneficial effects on diet pill use and unhealthy eating behaviors have been reported; however,...
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This article describes a program, PRODCLIN (distribution of the PRODuct Confidence Limits for INdirect effects), written for SAS, SPSS, and R, that computes confidence limits for the product of two normal random variables. The program is important because it can be used to obtain more accurate confidence limits for the indirect effect, as demonstra...
Article
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An intermediate endpoint is hypothesized to be in the middle of the causal sequence relating an independent variable to a dependent variable. The intermediate variable is also called a surrogate or mediating variable and the corresponding effect is called the mediated, surrogate endpoint, or intermediate endpoint effect. Clinical studies are often...
Article
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The most commonly used method to test an indirect effect is to divide the estimate of the indirect effect by its standard error and compare the resulting z statistic with a critical value from the standard normal distribution. Confidence limits for the indirect effect are also typically based on critical values from the standard normal distribution...
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The paper describes advances in statistical methods for prevention research with a particular focus on substance abuse prevention. Standard analysis methods are extended to the typical research designs and characteristics of the data collected in prevention research. Prevention research often includes longitudinal measurement, clustering of data in...
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We employed meta-analytic techniques to examine the validity of the claim that social support and social negativity are unrelated. It was hypothesized that the inverse relation between social support and social negativity increases as the specificity of the level of the assessment increases. A total of 280 effect sizes (e.g., concurrent correlation...
Article
To assess the deterrent effect of mandatory, random drug testing among high school (HS) athletes in a controlled setting. Two high schools, one with mandatory drug testing (DT) consent before sports participation, and a control school (C), without DT, were assessed during the 1999-2000 school year. Athletes (A) and nonathletes (NA) in each school c...
Article
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A Monte Carlo study compared 14 methods to test the statistical significance of the intervening variable effect. An intervening variable (mediator) transmits the effect of an independent variable to a dependent variable. The commonly used R. M. Baron and D. A. Kenny (1986) approach has low statistical power. Two methods based on the distribution of...
Article
Full-text available
A Monte Carlo study compared 14 methods to test the statistical significance of the intervening variable effect. An intervening variable (mediator) transmits the effect of an independent variable to a dependent variable. The commonly used R. M. Baron and D. A. Kenny (1986) approach has low statistical power. Two methods based on the distribution of...
Article
Full-text available
This paper describes the statistical similarities among mediation, confounding, and suppression. Each is quantified by measuring the change in the relationship between an independent and a dependent variable after adding a third variable to the analysis. Mediation and confounding are identical statistically and can be distinguished only on conceptu...

Citations

... Therefore, indirect effects were assessed using the Monte Carlo method. In this method, effects are estimated for the sample, a sampling distribution of the product of the independent and mediating variable are generated based on 1000 random samples with population values equal to the sample values, and lower and upper confidence intervals are generated based on this distribution [34]. This method has been shown to be comparable to other asymmetric methods and is appropriate for complex survey data [35]. ...
... The full model and the parsimonious model were compared using the Likelihood-ratio test. The standardized root mean square residual (SRMR) ≤ 0.08, comparative fit indices (CFI) ≥ 0.90, and Coefficient of Determination (CD) ≥ 0.90 were adopted to assess the adequacy of the measurement and structural models (MacKinnon, Lockwood, Hoffman, West, & Sheets, 2002). The significance level established for all analyses was 5% (p ≤ 0.05). ...
... Booster interventions give the opportunity to reinforce and build on information to suit students' age and development [44]. Booster sessions are common in the field of health promotion, including education about drugs [45], life style programs [46] or worksite interventions [47]. However, as organ donation registration is a onetime behaviour, booster sessions are not relevant anymore for students who already registered their decision. ...
... The relationship people have with their spouse or partner is an essential and integral factor in the lives of most individuals (Whisman and Baucom, 2012;Kazan et al., 2016). The social support individuals may receive from a spouse can be reflected in their well-being (Antonucci et al., 2001;Okun and Lockwood, 2003;Okabayashi et al., 2004). Individuals who are married or live in comparable relationships have been found to be happier and have better mental and physical health than singles (Gove et al., 1983;Holt-Lunstad et al., 2008;Kolves et al., 2012). ...
... 41 Despite this malleability, few multiple behavior change interventions target college-aged adults, 6 and those that have, found it difficult to achieve significant positive results. 7 A lack of knowledge about the psychosocial constructs that should be targeted has impeded success, 10,42 and a better understanding of between-behavior relationships and cross-behavior influences is needed. 11,22 The purpose of this study was to examine associations between PAI and EI among college-aged adults living in Hawai'i to provide guidance for future multiple behavior change research. ...
... SD = 55.41 weeks). Four studies and one editorial reported on the same intervention (Athletes Targeting Healthy Exercise and Nutrition Alternatives [ATHENA]; Elliot et al., 2004Elliot et al., , 2006Elliot et al., , 2008Gómez, 2004;Ranby et al., 2009). Of these, two studies reported on pre-test and immediate post-test effects of the intervention using the same sample of participants (Elliot et al., 2004(Elliot et al., , 2006, whereas one reported on the post-high school follow-up (1-to 3-year) effects of the intervention using a subsample of the participants (Elliot et al., 2008). ...
... In addition, although there was no significant correlation between high standards and parental burnout (see Table 1), high standards negatively predicted parental burnout when the effects of the other two child-oriented perfectionism scales were taken into account (see Regression Model A in Table 2). This may be due to the elimination of the suppression effect of high standards by controlling for their shared variance with discrepancy (see MacKinnon et al., 2000). There was a clear relation between emotional intelligence and parental burnout (see Table 1), and such an effect remained significant even when the child-oriented perfectionism scales were controlled for (see Regression Model B in Table 2). ...
... The main methods used to test for mediating effects include stepwise regression, Sobel test, and Bootstrap test (MacKinnonet al. 2002;Fritz and MacKinnon 2007;Hayes 2009). Although the stepwise regression method has the least statistical efficacy, it is more reliable when the coefficients are significant (MacKinnon et al. 2002). Therefore, we introduce a stepwise regression approach to test the mediating effect of urban form. ...
... Scientists usually utilize a basic trial configuration to test for the impact of past understanding of a skill on learning another skill (inter task transfer) or on playing out a similar skill in another specific circumstance (Goldberg et al., 2003). ...
... Este análisis fue considerado debido a que la variable de respuesta (la edad de inicio) es una variable que puede presentar censura, es decir, no todos los participantes en la encuesta pudieron haber experimentado el evento de consumir sustancias (Clark, Bradburn, Love, & Altman, 2003). Considerando lo anterior, además de la violación del supuesto de normalidad que presenta la variable tiempo en general (Gómez & Cobo, 2004), hace de esta técnica apropiada para el fenómeno de estudio, tal como otros autores han sugerido (Devi, 2015;MacKinnon & Lockwood, 2003;Singer & Willett, 1994) y como lo se ha llevado a cabo en otros trabajos similares previos (Herrera-Vázquez, Wagner, Velasco-Mondragón, Borges, & Lazcano-Ponce, 2004;Kosterman, Hawkins, Guo, Catalano, & Abbott, 2000;Trim, Schuckit, & Smith, 2010). ...