29.10 Matching for multiple treatments

In cases where you have multiple treatment groups, and you want to do matching, it’s important to have the same baseline (control) group. For more details, see

If you insist on using the MatchIt package, then see this answer


Lopez, Michael J, and Roee Gutman. 2017. “Estimation of Causal Effects with Multiple Treatments: A Review and New Ideas.” Statistical Science, 432–54.
McCaffrey, Daniel F, Beth Ann Griffin, Daniel Almirall, Mary Ellen Slaughter, Rajeev Ramchand, and Lane F Burgette. 2013. “A Tutorial on Propensity Score Estimation for Multiple Treatments Using Generalized Boosted Models.” Statistics in Medicine 32 (19): 3388–3414.
Zhao, Qin-Yu, Jing-Chao Luo, Ying Su, Yi-Jie Zhang, Guo-Wei Tu, and Zhe Luo. 2021. “Propensity Score Matching with r: Conventional Methods and New Features.” Annals of Translational Medicine 9 (9).