> -----Original Message-----
> From: Riano, Alejandro [mailto:[email protected]]
> Sent: Wednesday, September 25, 2002 5:02 PM
> To: [email protected]
> Subject: st: error checking
>
>
> I have a huge industrial survey which is a panel dataset. I
> have the id of
> the each firm and the region in which this firm is based. I'd
> like to check
> how many of the firms in this dataset have errors in the
> sense that the
> same id would be associated with a different region and/or
> that a given firm
> would have different year of foundation. (to have an idea of
> the % of errors
> in the database);
> I also want to know which ones are the "problematic" firms.
This should do it:
bysort firm (region): gen problem=!(region[1]==region[_N])
The logic here is that in a list sorted by region within firm, the first
and last records for a firm will be equal if and only if all records fro
the firm are in the same region.
With the dataset sorted by region within firm, this generates a variable
called problem, which equals zero if this holds, or one if not.
Then you can -tabulate-, -list-, or do whatever with th eproblem
records.
Nick W
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