This package is for analyzing ITS designs with parametric simulation and extrapolation
Active code is on github, with clean releases posted to CRAN.
I would recommend starting by reading the methods overview paper, “Using Simulation to Analyze Interrupted Time Series Designs”, on ArXiV https://arxiv.org/abs/2002.05746.
There is also a vignettes in the package that walks through almost everything.
The post-stratified ITS code is both messier and less developed. There are multiple ways one might adjust for time-varying covariates, and this is an active area of ongoing research. Buyer beware!
You are most welcome to check out a copy from github https://github.com/lmiratrix/simITS and play with the code. All suggestions and improvements most welcome!