sdid_event effect p-value

[Jakob Petersenn]

I am interested in using the combine() option offered with sdid_event and report the p-value in line with sdid (that does not have a combine option) - any suggestions?

Example 1 data from sdid_event help menu

clear
local GG = 19
local TT = 20
set seed 0
set obs `=`GG' * `TT''
gen G = mod(_n-1,`GG') + 1
gen T = floor((_n-1)/`GG') + 1
gen D = T > mod(G, 4) + 1 & G >= `GG'/4
gen Y = uniform() * (1 + D + 10*D*T)
sdid_event Y G T D, vce(bootstrap) placebo(all) combine(1 2 3 4 5)

Combined ATTs

             |  Estimate         SE      LB CI      UB CI  Switchers 
-------------+------------------------------------------------------
Cmb Effect 1 |  30.06605     2.3701   25.42065   34.71145         75