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From | tunmise jones <tunmisejones@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | st: Re:Grouping data/Probability Transition Matrix |
Date | Tue, 3 Apr 2012 02:20:00 +0100 |
Hello All, I am currently working with a balanced panel dataset of companies over a period of 9 years (1991-1999) to track employment growth over the period. I would like to group firms into 4 size classes based on size (employment) in 1991. Based on the size classes, I ran the following commands: gen InitialSize=0 Replace InitialSize=1 if emp<10& !mi(emp) & year==1991 Replace InitialSize=2 if emp>=10& emp<50& year==1991 Replace InitialSize=3 if emp>=50& emp<250 & year==1991 Replace InitialSize=4 if emp>=250& & year==1991 and obtained a four category dummy variable. I tried to group the entire dataset based on these categories and run separate regressions for each size class. It would appear observations for the regressions are only being limited to this sub-sample of firms in the first year. Following the above commands, 1. How can I classify all the firms into size classes based on their initial size (1991 size)? 2. Following from this, how can I estimate transition probability matrix for 1991 and 1999 to track firm mobility across the 4 size classes? I'll appreciate all the help I can get. Regards, Tunmise Jones * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/