Hi all,

I am doing a study where I measure the effect of a policy change on a dependent variable.

I am using an interrupted time series model with panel data and fixed effects. Is it correct to use this general regression: Yt = β0 + β1Tt + β2Xt + β3XtTt + εt and add a year fixed effect to recover the true post-effect? Or should I run this regression without the year fixed effect and only consider β3 for the post-effect?

Thanks in advance.

I am doing a study where I measure the effect of a policy change on a dependent variable.

I am using an interrupted time series model with panel data and fixed effects. Is it correct to use this general regression: Yt = β0 + β1Tt + β2Xt + β3XtTt + εt and add a year fixed effect to recover the true post-effect? Or should I run this regression without the year fixed effect and only consider β3 for the post-effect?

Thanks in advance.

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