First you have to identify the factors that you want to match (like age, weight/BMI e.t.c) between Treatment and Control group. Select the optimal match tolerance, the smaller the better. Remember to set "sampling without replacement". Do a t-test/Mann-whitney U test on factors that you used for matching between Treatment and Control in order to confirm that there is no statistical difference between factors. Then you can now do the t-test/mann-Whitney test on the outcome variable between Treatment and Control group.
Please let me know if the following references/sites are helpful to you in your quest:
1. Why Propensity Scores Should Not Be Used for Matching - Gary King
https://gking.harvard.edu/files/gking/files/psnot.pdfDec 16, 2016 ... We show that propensity score matching (PSM), an enormously popular ... proximates random matching which, we show, increases imbalance ...
2. An Introduction to Propensity Score Methods for Reducing the ...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3144483/Jun 8, 2011 ... Propensity score matching entails forming matched sets of treated and untreated subjects who share a similar value of the propensity score ...
3. Propensity Score Matching: Definition & Overview - Statistics How To
http://www.statisticshowto.com/propensity-score-matching/Feb 3, 2017 ... Statistics Definitions > Propensity Score Matching What is a Propensity Score? A propensity score is the probability that a unit with certain ...
4. Propensity-Score Matching (PSM)
http://cega.berkeley.edu/assets/cega_events/31/Matching_Methods.pptPropensity score matching: match treated and untreated observations on the estimated probability of being treated (propensity score). Most commonly used.
5. Understanding Propensity Scores
http://bayes.cs.ucla.edu/BOOK-09/ch11-3-5-final.pdf11.3.5 Understanding Propensity Scores. The method of propensity score ( Rosenbaum and Rubin 1983), or propensity score matching (PSM), is the most ...
Thank you Dennis Mazur for the sharing above. It is really informative. However, any idea on what is the most ideal match tolerance value for PSM? Any formula for it? Thanks