Issue: April 2013
eNews from The Methodology Center

The Methodology Center is pleased to release the latest version (1.3.0) of the SAS procedure PROC LCA for conducting latent class analysis. The software is available for download free of charge from the Methodology Center website. The download also contains PROC LTA, the SAS Procedure for latent transition analysis. For an overview of PROC LCA and PROC LTA features, please visit our website. New PROC LCA features include

  • Ability to assess identification of models with covariates via multiple random starts,
  • Indication of which latent class is the best match for each individual, and 
  • Option to generate 20 random draws for each individual's class membership based on posterior probabilities.

The users' guide has also been updated. Questions? Email


Download the software or read more.



Featured Article: Can We Prevent Children's Adjustment Problems by Teaching Parenting Skills?

Emotional problems between ages one and three are a risk factor for developing more serious problems later in life, and researchers sometimes seek to prevent these problems through parenting-skills education. In the article, "The Effects of the Family Foundations Prevention Program on Coparenting and Child Adjustment," to appear in Prevention Science, a team of Penn State researchers, including Methodology Center Principal Investigator Donna Coffman, examine the pathways through which one such prevention program works.


Read more.   


Innovation: Power Curves for Latent Class Analysis

Latent class analysis (LCA) is a tool used by behavioral scientists to identify subgroups within a population. When conducting LCA, choosing the number of classes (subgroups) in the model is a critical step. Some software, like the Methodology Center's Bootstrapping Macro for PROC LCA, allows users to perform the bootstrap likelihood ratio test (BLRT) to evaluate models with different numbers of classes. Until now, however, there has been no way to determine the sample size needed to provide sufficient power for detecting all of the underlying subgroups. In a new article by John Dziak, Stephanie Lanza, and Xianming Tan to appear in Structural Equation Modeling, the authors provide effect-size measures and power curves that can be used to predict power for the BLRT in LCA. These power curves can guide researchers in determining the sample size needed for their proposed LCAs.


Read more.   


Email for an advance copy of the article.



Methodology Center Director Linda Collins recently gave a talk at the National Institutes of Health (NIH) in Bethesda, Maryland, as part of the "Medicine: Mind the Gap" NIH Seminar Series. She discussed the multiphase optimization strategy (MOST) and how it can be used to optimize interventions for smoking cessation, drug abuse prevention, treatment of obesity, promotion of physical activity, and other health-related behaviors. The goal of the seminar series is to engage the NIH community in thought-provoking discussions about their role in helping to guide today's research. This high-resolution video provides an excellent introduction to MOST.


Watch the video.


Stream won't work? Download the video.


Download the slides.


In this special-edition podcast, host Aaron Wagner discusses sustainability with Methodology Center Green Team leaders Amanda Applegate and Tina Meyers. The conversation involves conservation efforts at the Center and around Penn State, as well as steps toward sustainability that anyone can take in their own home or office.


Download the podcast.


Never heard one of our podcasts? We have an archive of 16 podcasts that cover a broad range of methodological topics.


Browse the archive.



We created a special, April Fools' Day edition of our eNews. For the lighter side of methodology, take a look.  


Read the issue.  




A new program announcement from the National Institute on Nursing Research (NINR) and the National Cancer Institute (NCI), PA-13-165, seeks proposals using innovative research methods. The multiphase optimization strategy (MOST) and sequential, multiple assignment, randomized trial (SMART) are specifically mentioned as examples of the designs sought.  


Also see PA-13-077 and





College Enrollment Does Not Lead to Problem Drinking  

Despite high levels of binge drinking on college campuses, a new article by Methodology Center researchers suggests that college enrollment does not lead to substance abuse problems later in adulthood.   


Read more



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