Hello there,

have created three variables represing three classes (discrete) of travel times, naley 0-10, >10 -30, >30

Here the code

Code:
bys id oa11cd: egen totskillOA010 = sum(he_pop) if travtime_roadp99 <=10
bys id oa11cd: egen totskillOA030 = sum(he_pop) if  travtime_roadp99 > 10 & travtime_roadp99 <=30

bys id oa11cd: egen totskillOA060 = sum(he_pop) if travtime_roadp99 > 30
here example of areg

Code:
areg ltuemp ltotskillOA010  ltotskillOA030 ltotskillOA060 capempl  forown cost_sales  i.industry1 i.year i.size1 , absorb(cdu_id) cluster(cdu_id)

.no observations
r(2000);
Here is a an example of the data

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input long id float(ltuemp ltotskillOA010 ltotskillOA030 ltotskillOA060)
5359 11.695764 6.907755         . .
 406  12.11514        .  6.704414 .
2270 13.866335 9.704244         . .
3325 11.072207 6.993933         . .
 406 12.171023        .  6.704414 .
6286  4.169453 10.60485         . .
3325 10.967153 6.993933         . .
3325 10.834778 6.993933         . .
5359  10.15619 6.907755         . .
5202 13.744015        . 11.073738 .
end
label values id firmid
label def firmid 406 "GB01100044", modify
label def firmid 2270 "GB03486485", modify
label def firmid 3325 "GB04544254", modify
label def firmid 5202 "GB07121573", modify
label def firmid 5359 "GB07359182", modify
label def firmid 6286 "GB09361425", modify
The same classes as continuos haven't given any problem, if put one by one of course. But I wanted to assess the joint effect of the three classes on ltuemp which is my DepVar.

Hope someone can help

Best,
Dalila