Dear members,

This is an example from my data. I have firms and some information about them. The last column is the industry code. I have 12 industries ranging from 1 to 12. In xtprobit regression i aslo add year and industry dummies (i.year and i.industry_dummy). However. in regression results industry no1 does not appear in the list of industry dummies. It starts from 2 and goes till 12. There is no reason to omitt obs of that industry (all values are non-missing). .

Example generated by -dataex-. To install: ssc install dataex
clear
input str58 conm double fyear long gvkey float(all_patents jv_dummy sa_dummy firm_age firm_size_at firm_size_emp stock_jv stock_sa industry_dummy)
"ADC TELECOMMUNICATIONS INC" 1991 1013 15 0 1 12 5.510072 .8870679 0 0 9
"ADC TELECOMMUNICATIONS INC" 1992 1013 13 0 0 13 5.483809 .8342126 0 1 9
"ADC TELECOMMUNICATIONS INC" 1993 1013 16 0 1 14 5.634983 .900974 0 1 9
"ADC TELECOMMUNICATIONS INC" 1994 1013 13 1 0 15 5.813187 .9722929 0 2 9
"ADC TELECOMMUNICATIONS INC" 1995 1013 9 1 1 16 6.398733 1.0932647 1 1 9
"ADC TELECOMMUNICATIONS INC" 1996 1013 18 1 1 17 6.644785 1.5303947 3 4 9
"ADC TELECOMMUNICATIONS INC" 1997 1013 27 0 1 18 6.841939 1.779012 4 4 9
"ADC TELECOMMUNICATIONS INC" 1998 1013 38 0 1 19 7.170571 2.0834336 3 8 9
"ADC TELECOMMUNICATIONS INC" 1999 1013 62 0 1 20 7.422092 2.5994995 1 6 9
"ADC TELECOMMUNICATIONS INC" 2000 1013 81 0 1 21 8.286647 3.1113796 0 6 9
"ADC TELECOMMUNICATIONS INC" 2001 1013 132 0 1 22 7.823926 2.4884005 0 6 9
"ADC TELECOMMUNICATIONS INC" 2002 1013 96 0 0 23 7.042461 2.0281482 0 8 9
"ADC TELECOMMUNICATIONS INC" 2003 1013 48 0 1 24 7.167732 1.740466 0 7 9
"ADC TELECOMMUNICATIONS INC" 2004 1013 63 0 1 25 7.2641 2.014903 0 5 9
"ADC TELECOMMUNICATIONS INC" 2005 1013 94 0 1 26 7.336286 2.104134 0 4 9
"ADC TELECOMMUNICATIONS INC" 2006 1013 110 0 0 27 7.384859 2.1517622 0 5 9
"ADC TELECOMMUNICATIONS INC" 2007 1013 140 0 0 28 7.475793 2.2027647 0 3 9
"ADC TELECOMMUNICATIONS INC" 2008 1013 91 0 1 29 7.560601 2.360854 0 1 9
"AST RESEARCH INC" 1990 1055 7 0 1 5 5.781283 .838113 0 0 4
"AST RESEARCH INC" 1991 1055 7 0 1 6 6.185037 1.0851892 0 2 4
"AST RESEARCH INC" 1992 1055 12 0 0 7 6.364084 1.2697605 0 6 4
"AST RESEARCH INC" 1993 1055 22 1 1 8 6.786896 1.5060754 0 6 4
"AST RESEARCH INC" 1994 1055 16 0 1 9 6.91336 1.942619 3 9 4
"AST RESEARCH INC" 1995 1055 40 0 0 10 6.929029 1.8863118 3 8 4
"AST RESEARCH INC" 1996 1055 21 0 1 11 6.722698 1.4233493 3 8 4
"AEROFLEX INC" 1998 1056 3 0 1 21 4.821096 -.17197527 0 0 10
"AEROFLEX INC" 1999 1056 12 0 0 22 5.107254 .09531018 0 1 10
"AEROFLEX INC" 2000 1056 12 0 0 23 5.516275 .16551444 0 1 10
"AEROFLEX INC" 2001 1056 10 0 0 24 5.737385 .22314355 0 1 10
"AEROFLEX INC" 2002 1056 4 0 0 25 5.763513 .7080358 0 0 10
"AEROFLEX INC" 2003 1056 2 0 1 26 5.800958 .6205765 0 0 10
"AEROFLEX INC" 2004 1056 1 0 0 27 6.312444 .874635 0 1 10
"AEROFLEX INC" 2005 1056 . 0 0 28 6.379867 .9707789 0 1 10
"AEROFLEX INC" 2006 1056 . 0 0 29 6.458373 .9839494 0 1 10
"AVX CORP" 2001 1072 7 0 1 28 7.43343 2.5572274 0 0 11
"AVX CORP" 2002 1072 8 0 0 29 7.438685 2.549445 0 1 11
"AVX CORP" 2003 1072 9 0 0 30 7.419307 2.576422 0 1 11
"AVX CORP" 2004 1072 8 0 1 31 7.432335 2.484907 0 1 11
"AVX CORP" 2005 1072 4 0 0 32 7.423693 2.4932055 0 1 11
"AVX CORP" 2006 1072 15 0 0 33 7.549365 2.564949 0 1 11
"AVX CORP" 2007 1072 11 0 0 34 7.654006 2.6390574 0 1 11
"AVX CORP" 2008 1072 4 0 0 35 7.535045 2.2925348 0 0 11
"AVX CORP" 2009 1072 2 0 0 36 7.626323 2.360854 0 0 11
"AVX CORP" 2010 1072 . 0 0 37 7.749099 2.415914 0 0 11

end
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Best regards, Farid