Free Software for Data Analysis and Experimental Design from the Penn State Methodology Center

This technology demonstration presents new online resources and recent advances in SAS and Stata developed at The Methodology Center at Penn State. New and updated SAS procedures and macros, Stata plugins, and free-standing web-based applications for intensive longitudinal data, latent class analysis (LCA), adaptive interventions, and factorial designs will be showcased. All online resources will be available on the Center’s website at methodology.psu.edu; all software and corresponding users’ guides will be available free-of-charge on the website and will be distributed on USB drives at the annual meeting.

The following software will be demonstrated: (1) an updated SAS macro for estimating time-varying effect models that can model within-subject correlation; (2) a new Stata plugin for use with the LCA Stata Plugin to estimate the association between a latent class variable and a distal outcome; (3) a new Stata plugin for use with the LCA Stata Plugin to perform the bootstrap likelihood ratio test; (4) a new web-based application to conveniently generate random assignments of participants to conditions in factorial experiments; and (5) a new web-based application for conveniently estimating the sample size for a sequential, multiple assignment, randomized trial (SMART).

Information will be available about other online resources and software created and maintained by The Methodology Center at Penn State. Some of our other software products include a STATA plug-in to conduct LCA and a SAS PROC and R package to analyze data from SMART to inform development of adaptive interventions. Demonstrations and information will be presented in the context of empirical data on the etiology or prevention of substance use and related behaviors. Attention will be given to practical implementation of the statistical methods using the demonstrated software, as well as recent features that have been incorporated into the software. Attendees of the annual meeting will be able to provide suggestions for future online resource development.