Why is my propensity score match equal to 1?

candicetait — Mon, 07 Feb 2022 04:17:30 GMT

Hello,

I ran a psmatch procedure to match companies by size and roa in the same industry class (Fama-French 28) and it returned some matches with a propensity score of exactly 1.

I don't know why this has happened, can you help?

My code below:

proc psmatch data=m9 region=treated;
class treat ff48;
psmodel treat (treated="1")= size ff48;
match distance=lps method=Greedy(k=1) exact=ff48 caliper=0.5;
assess lps var=(size roa)/ weight=none plots=(boxplot barchart);
output out(obs=match)=OutEx4_&y matchid=_MatchID;
run;

Thank you in advance,

Candice

Re: Why is my propensity score match equal to 1?

Haris — Wed, 09 Feb 2022 18:25:56 GMT

Propensity score of 1 means that the probability of the target treatment is 100% for a company based on your model and the values of the covariates.

topic Why is my propensity score match equal to 1? in Statistical Procedures

Why is my propensity score match equal to 1?

Re: Why is my propensity score match equal to 1?