Matching may refer to matching markets (resource allocation) or the statistical technique that evaluates treatment effects. Use other tags such as [microeconomics] or [statistics] etc. in combination to clarify your question.
Matching may refer to matching markets or resource allocation problems; the most famous variant is the Stable Marriage problem. It may also refer to general resource allocation problems (one-sided, two-sided matching, trading cycles etc.) and its relation to graph theory and microeconomics.
Another kind of matching is a statistical technique commonly used in experiments that evaluates the effect of a treatment. A commonly used technique is propensity score matching.
