The stmixed package began as the accompanying Stata implementation for the methodology in:
Crowther MJ, Look MP, Riley RD. Multilevel mixed effects parametric survival models using adaptive Gauss-Hermite quadrature with application to recurrent events and individual participant data meta-analysis. Statistics in Medicine 2014;33(22):3844-3858.
stmixed has now become a wrapper function for merlin, which gives it a lot more capabilities. The new developments in stmixed are described in a recent Stata Journal paper:
Crowther MJ. Multilevel mixed effects parametric survival analysis: Estimation, simulation and application. Stata Journal 2019;19(4):931-949. (Pre-print: https://arxiv.org/abs/1709.06633)
The latest stable version of stmixed can be installed with:
ssc install stmixed
To install directly from this GitHub repository, use:
net install stmixed, from("https://raw.githubusercontent.com/RedDoorAnalytics/stmixed/main/")