Worksheet #5 CSDID

clear

local units = 30
local start = 1
local end 	= 60

local time = `end' - `start' + 1
local obsv = `units' * `time'
set obs `obsv'

egen id	   = seq(), b(`time')  
egen t 	   = seq(), f(`start') t(`end') 	

sort  id t
xtset id t


set seed 20211222

gen Y 	   		= 0		// outcome variable	
gen D 	   		= 0		// intervention variable
gen cohort      = .  	// treatment cohort
gen effect      = .		// treatment effect size
gen first_treat = .		// when the treatment happens for each cohort
gen rel_time	= .     // time - first_treat

levelsof id, local(lvls)
foreach x of local lvls {
	local chrt = runiformint(0,5)	
	replace cohort = `chrt' if id==`x'
}


levelsof cohort , local(lvls)  
foreach x of local lvls {
	
	local eff = runiformint(2,10)
		replace effect = `eff' if cohort==`x'
			
	local timing = runiformint(`start',`end' + 20)	// 
	replace first_treat = `timing' if cohort==`x'
	replace first_treat = . if first_treat > `end'
		replace D = 1 if cohort==`x' & t>= `timing' 
}

replace rel_time = t - first_treat
replace Y = id + t + cond(D==1, effect * rel_time, 0) + rnormal()

xtline Y, overlay legend(off)