Re: st: Combining observations based on filing date and firm ID number

[Nick Cox <njcoxstata@gmail.com>]

Look at -collapse-.

Nick
njcoxstata@gmail.com

On 2 February 2014 16:38, William Billik <wbillik@kent.edu> wrote:

> In trying to reformat panel data from long to wide for purposes of
> merging with other data sources, the following error is obtained,
> "date_variable not unique withing firm_ID variable, there are multiple
> observations at the same date_variable within firm_ID variable.
>
> The data is of activist and institutional shareholder transactions and
> is from SEC (regulator) filings.  Consequently, for any given date
> there may be multiple shareholder transactions for the same firm.
> Occasionally, there are even multiple entries for the same shareholder
> on the same date.  Therefore, in long form, the data has multiple
> observations (rows) for the same shareholder ID, the same firm ID and
> and same date, but with differing transaction values.  (Or the
> shareholder ID may differ, but the firm ID and the date are the same.)
>
> I want to generate a format of the data where there is one observation
> of the firm_ID, with the transactions totals by shareholder and date
> in a single firm row.  Alternatively, the combined transaction totals
> of all shareholders on a date, while less preferable, may be
> acceptable.  Ultimately, I would like the data to be in this format of
> one row per firm to allow for merging with other data bases containing
> firm specific data.
>
> This is my first foray into Stata, and I tried the -egen- command to
> generate a total transaction value, but without success. (Only
> generated a new variable equal to the transaction value of the
> shareholder on a given date.)
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