# similar groups and need for propensity score matching?

If t-tests show that there is no significant difference between the control and treatment groups, is there a need to do a propensity score matching?

Thank you, =sa

Read Ho, Imai, King, & Stuart (2007) who explain how to assess balance and why you should avoid using hypothesis tests to do so. You should check balance not just on the means (which is all that a t-test does) but also on the means of the squared and cubic terms and the interactions among variables. All this can be done easily in the cobalt R package (which I wrote for this purpose). If you only have slight imbalances in the covariates, you should control for them using regression rather than propensity score matching to retain as big a sample as you can. Propensity score matching can needlessly throw away information that could be useful in your outcome model.