Firm age using crsp and comp
Posted: 04 August 2015 09:27 PM   [ Ignore ]
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Hello, I am new to SAS coding and in the process of replicating a paper where the firm age is defined as the number of years since the firm first appears in the crsp database. I have merged crsp and compustat based on cnum with code that I found on wrds. When I create the age variable, this is the code that I use….

cyear=year(datadate);
start=year(st_date);
firmageyears = cyear-start;

Some of the observations turn up negative years. Is this correct? Thanks in advance for the help.

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Posted: 05 August 2015 09:51 AM   [ Ignore ]   [ # 1 ]
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hi,

Compustat Fundamental Annual uses the prospectus to fill in the years prior to IPO. So, these firmyears are before the IPO, and consequently will have a negative firm age.

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Joost

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Posted: 19 August 2015 08:39 AM   [ Ignore ]   [ # 2 ]
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Okay, that makes sense. Thanks!

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