Hi SAS community,   I need help turning this logic into a program. I am trying to count the number of visits (with the variable Count) based on unique dates. This is what my data looks like.   Dataset   data dsn; input PID $ Date  $ Place  Provider; datalines; 001 10/10/2019 11 456 001 10/11/2019 11 400 001 10/11/2019 11 400 001 10/12/2019 11 509 ; run;   I would want an accumulating variable (Count) in my output like this; PID Date Place Provider Count 001 10/10/2019 11 456 1 001 10/11/2019 11 400 2 001 10/11/2019 11 400 2 001 10/12/2019 11 509 3 Thank you. ... View more

Hello SAS Community,   I am trying to conduct a matched case-control study (based on propensity scores AND also using the exact approach). I tried using the PSMATCH procedure but I am getting these warnings:  WARNING: An effect for the logistic regression model is a linear combination of other effects. The coefficient of the effect is 0. WARNING: Some treated units have less than the specified K=3 matched controls because there are not enough available controls for these treated units.   I have SAS Base 9.4_M4 and SAS/STAT 14.2. Is this the reason for the warnings? I appreciate any suggestions. Note: "psmodel", "match" and "assess" all appear in red fonts in SAS. Below is my code: proc psmatch data = cohorts region = allobs; class Cohort Year Sex Race; psmodel Cohort(Treated='Diseased') = Year Sex Race Age_at_Surgery; match method = greedy(k=3) exact = Sex Race stat = ps caliper = 0.05; assess ps var = (Sex Race) / plots = all weight = none; output out(obs=match)=matcheddsn matchid = match_id; run;   ... View more