Why I got incorrect number of All obs after PROC PSMATCH procedure?

vivianwang — Wed, 04 Aug 2021 04:21:57 GMT

Hello SAS Community,

I'm doing 1:1 propensity score matching procedure

The data set contains 47366 samples (treatment=30694/ control=16672)

After PROC PSMATCH procedure, I got a table as below

The number of All Obs (Treatment) and All Obs (Control) is different from the original data set, 70 of the total sample were lost.

And I also got a warning: Some treated units do not have matched controls because there are not enough available controls for these treated units.

Is this problem related to the warning? How do I solve it?

proc psmatch data=B.HLP_ID_COMED  region=treated; 
class SEX statin c_htn c_dm c_os c_mg c_go c_as c_sch c_emd c_nd c_dp c_thy c_gl m_antihi m_bb m_diur m_ssri m_anticho  m_ppi m_glau ;
Psmodel statin (Treated='1')= AGE SEX c_htn c_dm c_os c_mg c_go c_as c_sch c_emd c_nd c_dp c_thy c_gl m_antihi m_bb m_diur m_ssri m_anticho  m_ppi m_glau; 
match method=greedy( k=1) exact=(SEX)  caliper=0.2 ; 
assess lps var=(AGE SEX c_htn c_dm c_os c_mg c_go c_as c_sch c_emd c_nd c_dp c_thy c_gl m_antihi m_bb m_diur m_ssri m_anticho  m_ppi m_glau)/plots=ALL  weight=none; 
output out(obs=match)=OUT_PSM matchid=_MatchID; run;

Re: Why I got incorrect number of All obs after PROC PSMATCH procedure?

Oligolas — Wed, 04 Aug 2021 09:44:08 GMT

Hi,

did you check if you have missings in your treatment variable?

Re: Why I got incorrect number of All obs after PROC PSMATCH procedure?

vivianwang — Wed, 04 Aug 2021 11:04:10 GMT

Thank you for your reply

I’ve checked the sample and there is no missing data.

Is there other explanations for the 70 lost from the sample?

Thank you!

topic Re: Why I got incorrect number of All obs after PROC PSMATCH procedure? in SAS Programming

Why I got incorrect number of All obs after PROC PSMATCH procedure?

Re: Why I got incorrect number of All obs after PROC PSMATCH procedure?

Re: Why I got incorrect number of All obs after PROC PSMATCH procedure?