Hello everyone, i have a dataset in long format, it contains information of 3,167 school's perfomance in a test by year. rbd is the school id. It looks like this:

Code:
rbd agno promedio 
1 2014  205.9502 
1 2015 191.57983
1 2016  194.0618 
1 2017  202.0082 
1 2018       205 
4 2014 263.53513        
4 2015 279.52362        
4 2016  270.3875       
4 2017  267.1192        
4 2018     277.5        
5 2014  288.3368        
5 2015 268.91162        
5 2016  257.3042        
5 2017 291.87463        
5 2018     269.5
I need to perform a simple regression model and store b1 coefficient. Before running the loop, i tried the commands for one rbd.


Code:
reg promedio agno if rbd==1
mat beta=e(b)
svmat double beta, names(matcol)
gen aux=.
sum betaagno if rbd==1
replace aux=r(mean) if rbd==1
after running that commands, my database look like thisthis is exactly what i need)

Code:
rbd agno promedio betaagno  beta_cons       aux
1 2014  205.9502   .8527954     -1519       .8527954
1 2015 191.57983                 .          .8527954
1 2016  194.0618                 .          .8527954
1 2017  202.0082                 .          .8527954
1 2018       205                 .          .8527954
4 2014 263.53513                 .                  .        .
4 2015 279.52362                 .                   .        .
4 2016  270.3875                 .                   .        .
4 2017  267.1192                 .                   .        .
4 2018     277.5                 .                   .        .
5 2014  288.3368                 .                   .        .
5 2015 268.91162                 .                   .        .
5 2016  257.3042                 .                   .        .
5 2017 291.87463                 .                   .        .
5 2018     269.5                 .                   .        .
I need help with the loop, i tried this:

Code:
forvalues i= 1/5 {
cap reg promedio agno if rbd==`i'
mat beta=e(b)
svmat double beta, names(matcol)
sum betaagno if rbd==`i'
replace aux=r(mean) if rbd==`i'
drop betaagno beta_cons
}
1)i think the commands to store b1 are not efficient to use it in a loop.
2) I dont know how i can especify to the software that there are missing id values. (rbd 2, 3 are missing)

please help.

José Antonio