Featured Article: Teens Becoming Regular Smokers: The Roles of Smoking Quantity and Nicotine Dependence

February 4, 2013

Nicotine dependence plays a central role in the development of regular smoking, but the relationship is reciprocal: nicotine dependence causes people to smoke more, and regular smoking leads to nicotine dependence. To understand how people become regular smokers, it is important to understand the roles that nicotine dependence and smoking quantity play in the frequency of smoking, and how the strengths of these relationships change over time. This issue is addressed in the article in Drug and Alcohol Dependence, “Time-varying effects of smoking quantity and nicotine dependence on adolescent smoking regularity,” by Arielle Selya, Lisa Dierker, Jennifer Rose, Donald Hedeker, Xianming Tan, Runze Li, and Robin Mermelstein.

Featured Article: Understanding Childhood Health Disparities with LCA

Understanding Childhood Health Disparities with LCA

January 4, 2013

Research indicates that early childhood is a critical period of life that impacts many long-term health outcomes. By understanding disparities in early childhood health among different segments of the U.S. population, researchers can address the greatest needs within our society. In the article “Measuring Early Childhood Health and Health Disparities: A New Approach” which appears in the Maternal and Child Health Journal, Penn State researchers Marianne Hillemeier, Stephanie Lanza, Nancy Landale, and Sal Oropesa provide one of the most comprehensive examinations to date of child health and health disparities in the United States. Traditionally, disparities have been examined in terms of a specific health problem (e.g., differential asthma or obesity rates across ethnicities or socio-economic groups). By applying latent class analysis (LCA)—a tool for identifying hidden subgroups in a population—to a national sample of four-year-old children, the authors were able to simultaneously examine several important components of health: health conditions (e.g., obesity, asthma), functioning (e.g., vision, hearing, overall activity level), fine motor skills, emotional wellness (e.g., empathy, externalizing behavior), social skills, and cognitive achievement, across ethnicities and socio-economic groups.

Featured Article: Does Attending College Lead to Later Drinking Problems?

October 26, 2012

College is often perceived as a risky environment for problem drinking, but recent studies indicate that individuals who attend college go on to engage in this behavior in adulthood at equal or lower rates than those who do not attend college; that is, that college may actually protect individuals from substance use behaviors in adulthood. These studies, however, often fail to account for selection bias: the fact that the people who attend college are different in many ways than people who do not attend college. In the article “Causal Inference in Latent Class Analysis,” which will appear in Structural Equation Modeling, Methodology Center researchers Stephanie Lanza and Donna Coffman implement two propensity score techniques for causal inference in latent class analysis (LCA) to determine whether college enrollment is protective or harmful for substance use behavior later in life.

Featured Article: Does it Really Matter How I Code My Data?

Effect Coding Versus Dummy Coding in Analysis of Data From Factorial Experiments September 18, 2012

Although it is commonly written in textbooks, researchers sometimes forget that how a categorical variable is coded determines the interpretation of its associated beta coefficient in regression analyses. In a new technical report, “Effect Coding Versus Dummy Coding in Analysis of Data From Factorial Experiments,” Methodology Center researchers Kari Kugler, Jessica Trail, John Dziak, and Linda Collins explain the differences between effect coding and dummy coding when the multiple regression approach is used to perform an ANOVA.

Featured Article: Gauging the Impact of an HIV Prevention Intervention

August 9, 2012

The Reducing Risky Relationships HIV (RRR-HIV) intervention was designed to decrease incorrect and dangerous thoughts about relationships in order to reduce risky sexual behavior among women being released from prison. Results showed that women who participated in the program engaged in less unprotected sex.

For future interventions, it is important to determine why this happened. Was it because, as hypothesized, the intervention changed their beliefs about relationships? Was it because the intervention reduced their substance use? Or were other factors at work? In a recent paper in the journal Nursing Research, Methodology Center Investigators Donna Coffman and Kari Kugler used propensity score methods to estimate the causal effect of the RRR-HIV intervention on unprotected sex. These methods are broadly applicable to measuring the impact of interventions that target a mediator in order to achieve a healthy outcome.

Featured Article: Curbing Dangerous Drinking and Sex During Spring Break

July 9, 2012

Multiple studies have shown that going on a trip with friends during spring break is a risk factor for behavior including dangerous drinking and sex. In a new article in the Journal of Studies on Alcohol and Drugs, Methodology Center Investigator Megan Patrick and coauthor Christine Lee examined data from 261 undergraduates and found that students had greater odds of engaging in risky sex when they possessed greater pre-spring break intentions to have sex, and when they had a stronger sense that sex on spring break is common among their peers. The authors also found that being on a trip on a given day is associated with more drinking and sex, controlling for the fact that people who go on shorter trips or no trip at all.

Featured Article: Quantile Regression for Analyzing Heterogeneity in Ultra-High Dimension

Runze Li April 24, 2012

In a new article in the Journal of the American Statistical Society, authors Lan Wang, Yichao Wu, and Runze Li describe a new approach to accommodating heterogeneity in ultrahigh-dimensional data. The authors advocate a more general interpretation of sparsity, which assumes that only a small number of covariates influence the conditional distribution of the response variable, given all candidate covariates.

Featured Article: Designing Adaptive Health Interventions

March 2012 Featured Article March 27, 2012

Adaptive health interventions are an increasingly important tool in behavioral health. They use individual variables (e.g., severity of condition, patient preferences) to adapt an intervention; then they dynamically use individual outcomes (e.g., response, adherence to treatment) to readapt the intervention. Altering the intensity or type of treatment can be critical to patient success when an individual is not responding, and it can reduce cost and burden when intensive treatment is no longer necessary. Sequential, multiple assignment, randomized trials (SMARTs) provide the high-quality data needed to construct effective adaptive interventions.

Featured Article: New Method Advances Knowledge about Smoking Cessation

Smoking February 22, 2012

Technological advances such as smart phones have facilitated the collection of intensive longitudinal data (ILD) in prevention science research. In a new article titled "Using the Time-Varying Effects Model (TVEM) to Examine Dynamic Associations Between Negative Affect and Self Confidence on Smoking Urges: Differences Between Successful Quitters and Relapsers" appearing in the journal Prevention Science, the authors demonstrate the advantage of applying TVEM to ILD.

Featured Article: Human Papillomavirus and Media Messages

January 4, 2012 Sanofi Pasteur, “Vaccination” October 9, 2008 via Flickr, Creative Commons Attribution.

In a new article in the Journal of Health Psychology, authors Rachel Smith and Roxanne Parrot examine how people think about human papillomavirus (HPV) with semantic network analysis. In this study, 309 undergraduate students were surveyed on their knowledge of HPV. Previous analyses of media coverage of HPV corresponded with the students’ answers, which suggests their mental images may have been influenced by media exposure.

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