PSmatch2

[ashraf abugroun]

Using psmatch2
How to do 2:1 nearest neighbour.
How to keep only matched cases.
The option:
keep if _weight==. would work only for 1:1 matching.

[William Lisowski]

How to do 2:1 nearest neighbour.

Use the neighbor(2) option.

How to keep only matched cases.
The option:
keep if _weight==. would work only for 1:1 matching.

I don't understand that. The output of help psmatch2 tells us

_weight. For nearest neighbor matching, it holds the frequency with which the observation is used as a match

so I would expect _weight==1 to indicated matched cases in 1:1 matching, and _weight>=1 & _weight<=2 to indicate matched cases used in 2:1 matching, and so forth.