The randomness of policy intervention time Xtreg ln_w did treated* $xlist i.year if union!=1 ,fe // We think the Union will influence the common trend of the processing group and the control group, So let's see union=0 The circumstances of Xtreg ln_w did treated $xlist i.year ,fe // If did Still significant, And treated The year before the implementation of these policies is not significant, That's good Xtreg ln_w did treated i.year ,fe // There is no control variable added to this } // This is equivalent to the interaction between the years before the implementation of the policy and the processing of dummy variables Tab year, gen(yrdum) // produce year dummy, One every year dummy Variable **DID Methods need to meet the five conditions test. Xtreg ln_w did time treated $xlist i.year, fe ** DID Part of, According to the matching data above Pstest $xlist, both graph // Test whether the covariates are balanced between the treatment group and the control groupĭrop if common = 0 // Remove observations that do not satisfy the common region assumption Psmatch2 treated $xlist, out(ln_w) logit ate neighbor(1) common caliper(.05) ties // By nearest neighbor matching, Here you can have outcome, You can also do without it Sort tmp // Organize the database randomly Gen tmp = runiform() // Generate random number Xtreg ln_w did time treated $xlist i.year, fe // You can do it, One dummy variable will be omitted Reg ln_w did time treated $xlist // So that's one OLS Return to, It can also be used. Gen did = timetreated // That's what needs to be estimated DID, That's the cross term Gen treated = (idcode >2000)&!missing(idcode) // The policy implementation place is idcode Greater than 2000 The place of Gen time = (year >= 77) & !missing(year) // The policy implementation time is 1977 year Sum ln_w $xlist // Statistical description of related variables Global xlist 'grade age age2 ttl_exp ttl_exp2 tenure tenure2 not_smsa south race' Xtset idcode year, delta(1) // Set up the panel Webuse nlswork // Use the system's own database PSM-DID,DID,RDD The operation of these popular methods of measurement classics, Yes do When the documents enter the econometric circle, they are directly extracted by the community. Econometric circle (ID: econometrics666) Welcome to contribute ( Recommendation ) Econometric circle, Measurement is OK

Stata dedlete xlist