Nearest Neighbor Matching using "Matching" Package

Question

I'm trying to apply "nearest neighbor matching algorithm" into "Matching" Package.

My objective is to have the matched data set from a PSM (Propensity score matching) which have the same number of treatment and control.

For example, at the beginning, I have 145 units of control group and 639 units of treatment group. As I explained, I want to have 145 units of control group and 145 units of treatment group after matching.

Even though, "MatchIt" package has the nearest neighbor algorithm, I think "Matching" package does not have the algorithm as far as know.

I really appreciate your reply.

Thanks.

Answer 1

The Matching package does have nearest neighbor matching; it's the default. You might need to set whether you want matching with or without replacement (in your case, you want without replacement). I recommend using the MatchIt package though; it's more convenient to use and provides the same options.