Stefano M. Iacus, Gary King, and Giuseppe Porro, "Matching for Causal Inference Without Balance Checking"; copy at http://gking.harvard.edu/files/abs/cem-abs.shtml. (Paper: PDF).

This paper is out of date; we have divided it into two separate papers. The original is still available above, but we have no plans for it to be updated or published. The current versions of the two successor papers are available here:

  1. Stefano M. Iacus, Gary King, and Giuseppe Porro, "Causal Inference Without Balance Checking: Coarsened Exact Matching"; copy at http://gking.harvard.edu/files/abs/cem-plus-abs.shtml. (Abstract: HTML | Paper: PDF).

  2. Stefano M. Iacus, Gary King, and Giuseppe Porro, "Multivariate Matching Methods That are Monotonic Imbalance Bounding"; copy at http://gking.harvard.edu/files/abs/cem-math-abs.shtml. (Abstract: HTML | Paper: PDF).

Also see related research.