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 From "Jenniffer Solorzano Mosquera" To Subject st: stratification matching, please advice!! Date Sun, 20 May 2012 13:20:59 +0200

```Hi everybody, please help!!!!

I have a question that I would appreciate you can give some hints.I need to run stratification matching and then present pre-treatment outcomes ttests after matching by quintiles of pscore, to check if the pre_treatment outcomes were actually balanced. What I did was :

1. -pscore PE  _IUO_1 _Ilisted_1 _IUOXlis_1_1  ent1_bGearing   ln_ent1_bTotalassetsthEUR change_cash_flow Age Age2 ent1_bCF_Ope _Iyear_entr_*, pscore(mypscore2) blockid(myquintiles2) comsup level(0.005) -

2.
After obtaining the pscore quantiles (myquintiles2 actually gave me 5 groups) I run the following for stratification matching:

-      g att = .
g seatt=.
g weight=.
g support=.
g treated=.
egen g1 = group(myquintiles2) // listed , NACE_1digit_3 , year_entry pscore_q2
levels g1, local(gr)
qui foreach j of local gr {
psmatch2 PE  ///
if g1==`j', pscore(pscore_2) out(exi1_aEBITDA_multiple) common
replace att = r(att) if  g1==`j' & e(sample)
replace seatt = r(seatt) if g1==`j' & e(sample)
replace weight=_weight if g1==`j' & e(sample)
replace support=_support if g1==`j' & e(sample)
replace treated=_treated if g1==`j' & e(sample) -

3. And then I try to test if after matching the difference in means of pre-acquisition  outcome is not significant between treated and non-treated:

-  levelsof pscore_2_q, local(gg)
foreach i of local gg {
preserve
keep if g1==`i' & support==1
pstest  ent1_bEBITDA_multiple , treated(treated) support(support) mweight(weight)
restore
} -

Is it ok? How do I test whether the ATT was significant or not considering that it was with stratification matching?.

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```