Generalized Propensity Score (GPS)
Implementation in R of the GPS method developed in
[1] Imbens, G. W.: The role of the propensity score in estimating dose-response functions. Biometrika 83, 760-710 (2000) [2] Imai, K., and van Dyk, D.A.: Causal inference with general treatment regimes: generalizing the propensity score. Journal of the American Statistical Association 99 (476), 854-866 (2004) [3] Hirano, K., and Imbens, G. W.: The Propensity Score with Continuous Treatments. in Applied Bayesian Modeling and Causal Inference from Incomplete-Data Perspectives, ed. A. Gelman and X.-L. Meng, New York: Wiley (2004)
I appliied this methodology in the analysis of real data producing a dose-response curve for physical therapy treatment. Results were reported at ICHPS 2011 conference, manuscript link: https://www.researchgate.net/publication/268390079_What_is_the_right_amount_of_utilization_in_Home_Health_Care