Dear Statalist,
I am using STATA 17 and have run into an issue with the xtlogit regression model I am working on. The model includes random effects and clustered standard errors at the state level. Each observation is a firm-year. I have also included year and city dummies in the model. I have noticed that the standard error for one of my control variables ("Control1"), a continuous firm-level variable, is missing in the output, but the issue is resolved when I switch to a normal logit model. Can anyone explain why this is happening and what steps I should take? Additionally, would it be acceptable to simply use the normal logit model instead? I have attached my code and output for your reference.
Thank you in advance!
I am using STATA 17 and have run into an issue with the xtlogit regression model I am working on. The model includes random effects and clustered standard errors at the state level. Each observation is a firm-year. I have also included year and city dummies in the model. I have noticed that the standard error for one of my control variables ("Control1"), a continuous firm-level variable, is missing in the output, but the issue is resolved when I switch to a normal logit model. Can anyone explain why this is happening and what steps I should take? Additionally, would it be acceptable to simply use the normal logit model instead? I have attached my code and output for your reference.
xtlogit DV control1 control2 control3 i.year i.cbsacode1 i.industry, re vce(cluster state)
-------------------------------------------------------------------------------------------
| Robust
DV | Coefficient std. err. z P>|z| [95% conf. interval]
--------------------------+----------------------------------------------------------------
Control1 | -5.914205 . . . . .
Control2 | .6409042 .078724 8.14 0.000 .486608 .7952003
Control3 | 1.61525 .1153349 14.00 0.000 1.389197 1.841302
-------------------------------------------------------------------------------------------
| Robust
DV | Coefficient std. err. z P>|z| [95% conf. interval]
--------------------------+----------------------------------------------------------------
Control1 | -5.914205 . . . . .
Control2 | .6409042 .078724 8.14 0.000 .486608 .7952003
Control3 | 1.61525 .1153349 14.00 0.000 1.389197 1.841302
logit DV control1 control2 control3 i.year i.cbsacode1 i.industry, vce(cluster state)
-------------------------------------------------------------------------------------------
| Robust
DV | Coefficient std. err. z P>|z| [95% conf. interval]
--------------------------+----------------------------------------------------------------
Control1 | -5.914214 .4270465 -13.85 0.000 -6.751209 -5.077218
Control2 | .6409045 .0795968 8.05 0.000 .4848976 .7969114
Control3 | 1.615251 .1135764 14.22 0.000 1.392645 1.837856
-------------------------------------------------------------------------------------------
| Robust
DV | Coefficient std. err. z P>|z| [95% conf. interval]
--------------------------+----------------------------------------------------------------
Control1 | -5.914214 .4270465 -13.85 0.000 -6.751209 -5.077218
Control2 | .6409045 .0795968 8.05 0.000 .4848976 .7969114
Control3 | 1.615251 .1135764 14.22 0.000 1.392645 1.837856

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