Two-way fixed effect

[Amalik]

Hi,

I am using the following code to run a two-way fixed effect. However, my regression estimates for some variables (semi, sm, osc and style) are coming out to be 0 which is quite unusual. Can anyone suggest why this would be happening?

ods exclude all;
proc glm data= have;
absorb fundid;
class obsdate;
      model y= Semi postyear semi*postyear sm osc turn exp flow lnsize lnage returnrank style obsdate / solution noint ;
ods output ParameterEstimates=results;   
run;
ods exclude none;

[PaigeMiller]

I wrote a description of why this happens:

Re: Interpreting Multivariate Linear Regression wi... - SAS Support Communities