The TVEM SAS macro estimates coefficients in a time-varying effect model. Traditional analytic methods assume that covariates have constant (i.e., time-invariant) effects on a time-varying outcome. The %TVEM macros are able to estimate the time-varying effects of covariates. The %TVEM macro suite includes convenient tools for the analysis of intensive longitudinal data.
The %TVEM Macro Suite includes
%TVEM_normal for normally distributed outcomes
%TVEM_logistic for logistic-distributed outcomes
%TVEM_poisson for Poisson-distributed outcomes
%TVEM_zip for outcomes with zero-inflated Poisson models, and
%GLIMMIX for generalized mixed effects models1.
Features of all TVEM SAS macros include
ability to handle complicated models
generation of plots for estimated coefficient functions
parameter estimates saved to SAS data file
ability to specify covariates that have constant effects or time-varying effects, and
accommodation different distributions (normal, logistic, Poisson, or zero-inflated Poisson) outcomes measured over time.
Option to plot odds ratios and 95% confidence bands for logistic distributions
Substantial revision of the plots produced by the macros
TVEM SAS Macro Suite (Version 2.1.1) [Software]. (2014). University Park: The Methodology Center, Penn State. Retrieved from http://methodology.psu.edu
Li, R., Tan, X., Huang, L., Wagner, A. T., & Yang, J. (2014). TVEM (time-varying effect model) SAS macro suite users' guide (Version 2.1.1). University Park: The Methodology Center, Penn State. Retrieved from http://methodology.psu.edu
1This macro was developed by SAS Institute Inc. It is automatically called by the %TVEM macros when needed.