// 	Barbara Sianesi
//	Stata Users' Group Meeting -- London, September 10, 2010
//	PSMATCH2 EXAMPLE	 


use nsw_psid, clear
desc
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ta treated
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// 	Propensity score   								
/************************************************************************/
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dprobit treated age black hispanic married educ nodegree re75
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cap drop score
predict double score
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// 	Common support    								
/************************************************************************/
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summarize score if treated==1, detail
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summarize score if treated==0, detail
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density2 score, group(treated)
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psgraph, treated(treated) pscore(score) bin(50)
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// 	Nearest neighbour without replacement without caliper            						
/************************************************************************/
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psmatch2 treated, pscore(score) outcome(re78) noreplacement
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pstest2 age black hispanic married educ nodegree re75, sum graph
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// 	Nearest neighbour without replacement within caliper            							
/************************************************************************/
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psmatch2 treated, pscore(score) outcome(re78) noreplacement caliper(0.01)
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summarize _support if treated==1
display  1-r(mean)
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psgraph
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pstest2 age black hispanic married educ nodegree re75, sum graph
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// 	Nearest neighbour with replacement             							
/************************************************************************/
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psmatch2 treated, pscore(score) outcome(re78) 
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summarize _pdif, detail
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psmatch2 treated, pscore(score) outcome(re78) caliper(0.01)
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summarize _support if treated==1
display  1-r(mean)
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tab _weight if treated==0
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psgraph
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density2 score, g(treated) 
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density2 score, g(treated) m(_weight)
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pstest2 age black hispanic married educ nodegree re75, sum graph
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density2 re75 if re75<40000, g(treated) 
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density2 re75 if re75<40000, g(treated) m(_weight)
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//	>1-to-1  matching   								
/************************************************************************/
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psmatch2 treated, pscore(score) outcome(re78) neigh(10)
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psmatch2 treated, pscore(score) outcome(re78) neigh(20)
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psmatch2 treated, pscore(score) outcome(re78) neigh(10) cal(0.01)
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tab _nn if treated==1
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psmatch2 treated, pscore(score) outcome(re78) neigh(20) cal(0.01)
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tab _nn if treated==1
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//	Kernel matching        								
/************************************************************************/
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psmatch2 treated, pscore(score) outcome(re78) kernel k(epan)   bw(0.06)
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psmatch2 treated, pscore(score) outcome(re78) kernel k(normal) bw(0.06)
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psmatch2 treated, pscore(score) outcome(re78) kernel k(epan)   bw(0.01)
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psmatch2 treated, pscore(score) outcome(re78) kernel k(normal) bw(0.01)
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// 	Mahalanobis-metric matching 							
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psmatch2 treated, mahal(age black hispanic married educ nodegree re75) outcome(re78) 
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pstest2 age black hispanic married educ nodegree re75, sum graph
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psmatch2 treated, mahal(score age black hispanic married educ nodegree re75) outcome(re78) 
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pstest2 age black hispanic married educ nodegree re75, sum graph
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// 	ATNT 											
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gen treat0 = 1-treated
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psmatch2 treat0 age black hispanic married educ nodegree re75, outcome(re78)
* Remember to take -1*(effect) for ATNT.
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sum _pdif, d
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psmatch2 treat0 age black hispanic married educ nodegree re75, outcome(re78) cal(0.01)
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tab _weight if treat0==0
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pstest2 age black hispanic married educ nodegree re75, sum graph
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psmatch2 treated age black hispanic married educ nodegree re75, outcome(re78) kernel ate  
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film re78 treated age black hispanic married educ nodegree re75, ate  
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qui regress re78 treated##c.age treated##black treated##hispanic treated##married treated##c.educ treated##nodegree treated##c.re75
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margins, dydx(treated)
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margins, dydx(treated) over(treated)
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