The main goal of this study was to illustrate and provide some direction for dealing with the complexities of propensity score matching within different multilevel contexts. Special attention is given to how procedures typically applied in a non-hierarchical setting may be modified to properly reduce the expected bias in the estimated treatment…

Presented at the quarterly meeting of the New York Area SAS Users-Group in December 2008. In virtually any research context, there is likely to be opportunity to apply mixed-models--of which repeated-measures, multilevel, hierarchical and random- and fixed-effect models are specific types-- that improve upon their traditional linear or generalized…