pretrends--command written by Jonathen ROth

[Collin James]

Hi there,

Does anyone have experience with the "pretrends" command (https://github.com/mcaceresb/stata-pretrends#pretrends). I am trying to implement it with the code below but it really won't run. My data set is not that large (a couple thousand observations) and I left it over night and it was still working. I am wondering if something is wrong in my intuition. I tried it with reghdfe as well and that didn't seem to work. Thanks in advance.

preserve
keep if age>=17 & age<=23
*pretrend analysis
gen rel_date0=0
gen rel_date1=0
gen rel_date2=0
gen rel_date3=0
gen rel_date4=0
gen rel_date5=0
gen rel_date6=0
gen rel_date7=0
gen rel_date8=0
gen rel_date9=0
gen rel_date10=0
gen rel_date11=0
gen rel_date12=0
gen rel_date13=0
gen rel_date14=0
gen rel_date15=0


replace rel_date0=1 if time==`=tm(2022m6)'
replace rel_date1=1 if time==`=tm(2022m7)'
replace rel_date2=1 if time==`=tm(2022m8)'
replace rel_date3=1 if time==`=tm(2022m9)'
replace rel_date4=1 if time==`=tm(2022m10)'
replace rel_date5=1 if time==`=tm(2022m11)'
replace rel_date6=1 if time==`=tm(2022m12)'
replace rel_date7=1 if time==`=tm(2023m1)'
replace rel_date8=1 if time==`=tm(2023m2)'
replace rel_date9=1 if time==`=tm(2023m3)'
replace rel_date10=1 if time==`=tm(2023m4)'
replace rel_date11=1 if time==`=tm(2023m5)'
replace rel_date12=1 if time==`=tm(2023m6)'
replace rel_date13=1 if time==`=tm(2023m7)'
replace rel_date14=1 if time==`=tm(2023m8)'
replace rel_date15=1 if time==`=tm(2023m9)'

*reldatexage
foreach x of numlist 0/15 {
    gen rel_x_age`x'=rel_date`x'*age2
}

label var rel_date0 "-12"
label var rel_date1 "-11"
label var rel_date2 "-10"
label var rel_date3 "-9"
label var rel_date4 "-8"
label var rel_date5 "-7"
label var rel_date6 "-6"
label var rel_date7 "-5"
label var rel_date8 "-4"
label var rel_date9 "-3"
label var rel_date10 "-2"
label var rel_date11 "-1"
label var rel_date12 "0"
label var rel_date13 "1"
label var rel_date14 "2"
label var rel_date15 "3"

foreach v of varlist hi_ed  da_all mh_all mh_inpatient mh_crisis mh_outpatient jpo_all acj_jail_all_act_ind hous_all hous_emerg hous_prevent padhs_all padhs_snap padli_ui_benefits_act_ind ccac_all bhs_all total_day  {
areg `v' rel_x_age0-rel_x_age9 o.rel_x_age11 rel_x_age12-rel_x_age15 rel_date0-rel_date15 c.age2 i.time, absorb(mci)
pretrends power 0.8, pre(1/11) post(12/15)
coefplot, keep(rel_x_age*) vertical base omitted msymbol(diamond) ///
        xtitle("Time") ytitle("`V'")  title("`v'") ///
        mcolor("106 208 200") ciopts(lcolor("118 152 160")) ///
        yline(0,lcolor("106 208 200") lpattern(dash)) xline(11.5, ///
        lpattern(dash) lcolor(red)) scale(.8) xsize(9) ysize(7) ///
        graphregion(fcolor(white) ifcolor(white) ilcolor(white)) ///
        xscale(lcolor("0 51 102")) yscale(lcolor("0 51 102")) coeflabels(, truncate(10) angle(45)) ///
        xlabel(, labcolor("0 51 102") noticks)
graph save "`home'eventstudy_`v'_3m_2", replace
graph export "`home'eventstudy`v'_3m_2.png", as(png) replace
}

[Mauricio Caceres]

It's not usually possible to debug without knowing what type of issue you're having. My only guess is that you might want to include the -omit- option and see if that works, but otherwise you don't even specify what the error is, exactly.

[Collin James]

So, no error shows up--it is just that I left this to run all night and it still didn't complete. Wheel still spinning, etc! So I feel like there is something wrong here.

[Collin James]

Ok, I redownloaded it from github (the newer version of it, looks like I may have had an old version). Same code, but now I get:

warning: option b() detected without option vcov()
PreTrendsPower(): Power level 80% too low; please increase power.
PreTrendsPower(): 198 Stata returned error
PreTrends(): - function returned error
<istmt>: - function returned error

[Mauricio Caceres]

If you post the estimates I can check it out (b and V).