bysort firm personid: gen count=_N if year==1993 | year==1994
* Count would equal to 2 if a person is with the same firm for both
1993 and 1994, 1 if this person was only with this firm in 1993 or in
1994.
bysort firm year: egen changed=total(count) if count==1 & year==1993
variable changed would contain the number of employees who were with
this firm in 1993, but no longer remain employed with the same
employer in 1994. it'd be all missing values for this variable in
1994.
On 8/13/06, Wanli Zhao <[email protected]> wrote:
Guys, please help me with a data management question. I spent a day and
cannot figure out.
I have panel dataset, which has firm ID, year, and person ID for the people
working in the firm. I want to calculate the number of staff changes for the
same company for each year. For example, the data is as follows.
FIRM YEAR PERSONID
1 1993 2
1 1993 4
1 1993 276
1 1993 23456
1 1993 853
1 1994 2
1 1994 276
1 1994 853
1 1994 3452
1 1994 224
I already sort firm and year. As you can see, the change of staff for firm 1
in 1994 should be 2 because only person 2, 276 and 853 are retained. I only
want to count how many persons are missing from previous year. I appreciate
your kind help.
Wanli
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--
Ada Ma
Research Fellow
Health Economics Research Unit
University of Aberdeen, UK.
http://www.abdn.ac.uk/heru/
Tel: +44 (0) 1224 553863
Fax: +44 (0) 1224 550926
*
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