# Health economic simulation modeling

## Overview

`hesim`

is a modular and computationally efficient R package for health economic simulation modeling and decision analysis that provides a general framework for integrating statistical analyses with economic evaluation. The package supports cohort discrete time state transition models (DTSTMs), N-state partitioned survival models (PSMs), and individual-level continuous time state transition models (CTSTMs), encompassing both Markov (time-homogeneous and time-inhomogeneous) and semi-Markov processes. It heavily utilizes `Rcpp`

and `data.table`

, making individual-level simulation, probabilistic sensitivity analysis (PSA), and incorporation of patient heterogeneity fast.

Features of the current version can be summarized as follows:

- Cohort DTSTMs, individual-level CTSTMs, and N-state PSMs that encompass Markov and semi-Markov processes
- Options to build models directly from fitted statistical models or by defining them in terms of expressions
- Parameter estimates from either an
`R`

based model or from an external source
- Convenience functions for sampling model parameters from parametric distributions or via bootstrapping
- Parameter uncertainty propagated with PSA
- Modeling patient heterogeneity
- Performing cost-effectiveness analyses and representing decision uncertainty from PSAs
- Simulation code written in
`C++`

to boost performance

## Installation

You can install the current release from CRAN or the most up to date development version from GitHub.

```
# Install from CRAN:
install.packages("hesim")
# Install the development version from GitHub:
# install.packages("devtools")
devtools::install_github("hesim-dev/hesim")
```