Dear All, I have this data set.
Code:
* Example generated by -dataex-. For more info, type help dataex
clear
input byte firm int year str30 auditorfirm
 3 2005 "Deloitte & Touche LLP155 E Bro"
 3 2006 "Deloitte & Touche LLP155 E. Br"
 3 2007 "Deloitte & Touche155 E. Broad"
 3 2008 "Deloitte & Touche155 E. Broad"
 3 2009 "Deloitte & Touche155 E. Broad"
 3 2010 "Deloitte & Touche180 E. Broad"
 3 2011 "Deloitte & Touche180 E. Broad"
 3 2012 "Deloitte & Touche  180 E. Broa"
 3 2013 "Deloitte & Touche 180 E. Broad"
 3 2014 "Deloitte & Touche 180 E. Broad"
 3 2015 "Deloitte & Touche 180 E. Broad"
 3 2016 "Deloitte & Touche 180 E. Broad"
 3 2017 "Deloitte & Touche 180 E. Broad"
 3 2018 "Deloitte & Touche 180 E. Broad"
 3 2019 "Deloitte & Touche 180 E. Broad"
 3 2020 "DELOITTE & TOUCHE 180 E. BR"  
 4 2005 "Ernst & Young, LLP. Two Commer"
 4 2006 "Ernst & Young LLP, Two Commerc"
 4 2007 "Ernst & Young LLP, Two Commerc"
 4 2008 "Ernst & Young LLP, Two Commerc"
 4 2009 "ERNST & YOUNG LLP, TWO COMMERC"
 4 2010 "ERNST & YOUNG LLP, TWO COMMERC"
 4 2011 "Egan & Egan, CPA's  20910 Mart"
 4 2012 "Egan & Egan, CPA's  20910 Mart"
 4 2013 "Egan & Egan, CPA's  1545 N. Co"
 4 2014 "Egan & Egan, CPA's  1545 N. Co"
 4 2015 "Egan & Egan, CPA's  1545 N. Co"
 4 2016 "Egan & Egan, CPA's  1545 N. Co"
 4 2017 "Egan & Egan, CPA's  1545 N. Co"
 4 2018 "Egan & Egan, CPA's  1545 N. Co"
 4 2019 "Egan & Egan, CPA's  1545 N. Co"
 4 2020 "Egan & Egan CPA's  1545 N."    
 6 2005 "DELOITTE & TOUCHE LLP, TWO HIL"
 6 2006 "DELOITTE & TOUCHE LLP, TWO HIL"
 6 2007 "DELOITTE & TOUCHE LLP, TWO HIL"
 6 2008 "DELOITTE & TOUCHE LLP, TWO HIL"
 6 2009 "DELOITTE & TOUCHE LLP, TWO HIL"
 6 2010 "DELOITTE & TOUCHE LLP, TWO HIL"
 6 2011 "DELOITTE & TOUCHE LLP, TWO HIL"
 6 2012 "DELOITTE & TOUCHE LLP, TWO HIL"
 6 2013 "DELOITTE & TOUCHE LLP,185 ASYL"
 6 2014 "DELOITTE & TOUCHE LLP,185 ASYL"
 6 2015 "DELOITTE & TOUCHE LLP,185 ASYL"
 6 2016 "ERNST & YOUNG LLP 5 TIMES SQUA"
 6 2017 "ERNST & YOUNG LLP 5 TIMES SQU"
 6 2018 "ERNST & YOUNG LLP 5 TIMES SQU"
 6 2019 "Ernst & Young, LLP, 560 Missio"
 6 2020 "Ernst & Young LLP 560 Missi"  
 7 2005 "Piercy, Bowler, Taylor, Kerns,"
 7 2006 "Piercy, Bowler, Taylor, Kerns,"
 7 2007 "Insurance Industry Auditing &"
 7 2008 "Insurance Industry Auditing &"
 7 2009 "Insurance Industry Auditing an"
 7 2010 "Insurance Industry Auditing an"
 7 2011 "Ernst & Young, 999 Third Avenu"
 7 2012 "Ernst & Young, 999 Third Avenu"
 7 2013 "Ernst & Young, 999 Third Avenu"
 7 2014 "Johnson Lambert LLP, 700 Sprin"
 7 2015 "JOHNSON LAMBERT LLP, 700 SPRIN"
 7 2016 "STROHM BALLWEG, LLP  9701 BRAD"
 7 2017 "STROHM BALLWEG, LLP  9701 BRAD"
 7 2018 "STROHM BALLWEG, LLP  9701 BRAD"
 7 2019 "STROHM BALLWEG, LLP  9701 BRAD"
 7 2020 "STROHM BALLWEG LLP  9701 BR"  
 8 2005 "Larson & Company - 99065 S 130"
 8 2006 "Larson & Company - 99065 S 130"
 8 2007 "Larson and Company - 99065 S 1"
 8 2008 "Larson & Rosenberger LLP, 9065"
 8 2009 "Larson & Rosenberger LLP, 9065"
 8 2010 "Larson & Rosenberger LLP, 9065"
 9 2005 "VILLAFANE & OTI CPAs Parana St"
 9 2006 ""                              
 9 2007 "Villafane & Oti PSC"          
 9 2008 "Villafae & Oti PSC"            
11 2006 "STROHM BALLWEG, LLP.  -  MADIS"
11 2007 "STROHM BALLWEG, LLP"          
11 2010 "STROHM BALLWEG, LLP, 999 FOURI"
11 2011 "STROHM BALLWEG, LLP, 999 FOURI"
11 2012 "STROHM BALLWEG, LLP, 999 FOURI"
11 2014 "STROHM BALLWEG, LLP9701 BRADER"
11 2015 "STROHM BALLWEG, LLP9701 BRADER"
11 2016 "STROHM BALLWEG, LLP9701 BRADER"
11 2018 "STROHM BALLWEG INC"            
11 2019 "STROHM BALLWEG INC9701 BRADER"
11 2020 "STROHM BALLWEG INC9701 BRAD"  
14 2005 "Ernst & Young, LLP, 200 Claren"
14 2006 "Ernst & Young, LLP 200 Clarend"
14 2007 "Ernst & Young, LLP 200 Clarend"
14 2008 "Ernst & Young, LLP 200 Clarend"
14 2009 "Ernst & Young, LLP 200 Clarend"
14 2010 "Ernst & Young, LLP 200 Clarend"
14 2011 "Ernst & Young, LLP 200 Clarend"
14 2012 "Ernst & Young, LLP 200 Clarend"
14 2013 "Ernst & Young, LLP 200 Clarend"
14 2014 "Ernst & Young, LLP 200 Clarend"
14 2015 "Ernst & Young, LLP 200 Clarend"
14 2016 "Ernst & Young, LLP 200 Clarend"
14 2017 "Ernst & Young, LLP 200 Clarend"
14 2018 "Ernst & Young, LLP 200 Clarend"
14 2019 "Ernst & Young, LLP 200 Clarend"
end
For each firm, I'd like to know whether its audit firm has been changed (in some particular years), according to the name of `auditorfirm'. However, as you can see, the names of the same audit firm might differ.
For instance, for firm = 3, its audit firm is the same for all years but with different (but similar) names. I wonder if there is a way to deal with this kind of problem? Thanks.