Without Replacement Treatment and Control Firms

amanjot_42 — Wed, 16 Sep 2020 01:05:57 GMT

Hi all,

I am trying to come up with control firms for treatment firms in the sample. It is a cross-sectional data, and I want one control firm (matched within the same industry code and closest propensity score) for each treatment firm. So, one-on-one matching for a treatment-control pair.

If firm B can act as a control firm for firm A (based on the criteria, i.e. same industry code and closest propensity), then it should not act as a control for any other firm. However, the next best alternative should be used as a control firm, i.e. within the same industry code, but the next best closest propensity score.

firm_id Treatment_indicator Industry_code Pscore

1111 0 11 0.35

1112 1 11 0.44

1113 0 12 0.60

1114 0 15 0.80

1115 1 17 0.56

After creating two separate files for treatment and control firms, I am using this code (I got it from previous posts):

data treatment_firms conrol_firms;
set have;
if treatment_indicator = 0 then output control_firms;
if treatment_indicator = 1 then output treatment_firms;
run;

proc sql;
create table like_each_other as
select O.*, T.firm_id as Tfirm_id, abs(O.pscore-T.pscore) as P_Diff
from control_firms as O inner join treatment_firms as T
on o.industry_code=t.industry_code
order by tfirm_id;
quit;

proc means data=like_each_other noprint;
by Tfirm_id;
output out=close_match idgroup(min(P_diff) out[1] (firm_id)=);
run;

Can you please help in coming up with the correct codes? These codes are working on 'with replacement' basis, so, one control firm is chosen as a 'control firm' for another treatment firm as well. I want one firm to act as a control for only one treatment firm.

Regards,
Aman

Re: Without Replacement Treatment and Control Firms

pink_poodle — Wed, 16 Sep 2020 15:46:52 GMT

We do not want to re-invent the PSMATCH procedure here. The default for this procedure is without replacement, so it will suit just fine:
https://documentation.sas.com/?docsetId=statug&docsetVersion=14.2&docsetTarget=statug_psmatch_syntax06.htm&locale=en
Here is a nice example to work from (omit "method=replace" for without replacement):
https://documentation.sas.com/?docsetId=statug&docsetTarget=statug_psmatch_examples05.htm%3Flocale&docsetVersion=14.2&locale=en

topic Without Replacement Treatment and Control Firms in SAS Programming

Without Replacement Treatment and Control Firms

Re: Without Replacement Treatment and Control Firms