Toolkit for Weighting and Analysis of Nonequivalent Groups

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

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.

Table of Contents

  • Chapter One


  • Chapter Two

    Setting Up

  • Chapter Three

    Treatment Assignment Models

  • Chapter Four

    Evaluating the Quality of the IPTW

  • Chapter Five

    Analysis of Outcomes

  • Chapter Six

    Data Outputs

Research conducted by

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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