Hello Ryan, Thanks for your answer. Yes, I mistyped here the variable high_sensitive but not in the SAS program. In fact, I tried with this code for year fixed effect after reviewing the book Fixed Effects Regression Methods for Longitudinal data with SAS. Proc logistic data=Exam.Alltables Desc; class Year /PARAM=REF ; model disclosure = Year Div_emissions Emissions_trading_num Assets_LN High_sensitive_num EPA_num; STRATA Year; run; However, my concern is about Firm fixed effect. There are around 600 companies for each year (4 years). The results are truly different. All the variables are dropped out. Proc logistic data=Exam.Alltables Desc; class Company_ID /PARAM=REF ; model disclosure = Company_ID Div_emissions Emissions_trading_num Assets_LN High_sensitive_num EPA_num; STRATA Company_ID; run; Please find enclosed sample data
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