xtdidregress imposes a single coefficient, which is often too restrictive. Can you show exactly what you did?
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. xthdidregress twfe (hard_final_Exact_new Firm_Size_w ROA_w Leverage_w Market_book_four_w Non_pension_CFO_w STD_CFO_w Board_Inde
> pendence_w BoardSize_w Gender_Diversity_w Fund_Status_w FUNDING_RATIO_w Platn_Size_w CSR_Committee SustainabilityScore_w i.year
> i.ff_12) (csopresence1), group(id)
note: variable _did_cohort, containing cohort indicators formed by treatment variable csopresence1 and group variable id, was
added to the dataset.
units in time period 2004 cannot be treated
The first time period in the estimation sample is 2004. This implies units are either always treated or are switching
between treatment and control, which violates the model's assumptions. You may look at variable _did_cohort to diagnose
this behavior.
r(498);
. replace csopresence1 = 0 if year < 2005
(2,516 real changes made)
. xthdidregress twfe (hard_final_Exact_new Firm_Size_w ROA_w Leverage_w Market_book_four_w Non_pension_CFO_w STD_CFO_w Board_Inde
> pendence_w BoardSize_w Gender_Diversity_w Fund_Status_w FUNDING_RATIO_w Platn_Size_w CSR_Committee SustainabilityScore_w i.year
> i.ff_12) (csopresence1), group(id)
note: variable _did_cohort, containing cohort indicators formed by treatment variable csopresence1 and group variable id, was
added to the dataset.
invalid treatment
The treatment is assumed to be staggered. Once a unit is treated, it should remain treated.
r(498);
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