Cover: Toolkit for Weighting and Analysis of Nonequivalent Groups

Toolkit for Weighting and Analysis of Nonequivalent Groups

A Tutorial on the TWANG Shiny Application for Time-Varying Treatments

Published May 14, 2021

by Beth Ann Griffin, Ricardo Sanchez, Christopher E. Maerzluft, Matthew Cefalu, Lane F. Burgette, Daniel F. McCaffrey

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This tool describes how to use a menu-driven Shiny application (app) based on the Toolkit for Weighting and Analysis of Nonequivalent Groups (TWANG) R package. The TWANG package was first developed in 2004 by RAND Corporation researchers for the R statistical computing language and environment. The RAND team has now developed interactive, menu-driven apps of the original TWANG functions using the Shiny software development package. Shiny is an R package that makes it easy to build interactive web apps straight from R.

This tutorial provides an introduction on how to use our TWANG Shiny app for time-varying treatments. The tutorial demonstrates use of the Shiny app through an illustrative example and explains key inputs and outputs of the TWANG Shiny app for time-varying treatments. More specifically, it provides an introduction about how to use the TWANG Shiny app for time-varying treatments to estimate the inverse probability of treatment weights (IPTW) for time-varying treatments when using observational data and to calculate treatment effect estimates using those IPTW.

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This research was funded by the National Institute on Drug Abuse and conducted by the Justice Policy Program within RAND Social and Economic Well-Being.

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