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Re: st: Merge data for two panels in a panel data set

 From Eric Booth <[email protected]> To [email protected] Subject Re: st: Merge data for two panels in a panel data set Date Mon, 26 Mar 2012 09:48:57 -0500

```On Mar 26, 2012, at 9:35 AM, [email protected] wrote:

> Dear all,
>
> I have two firms in a data set that merge at a given point of time. For a specific reason, I need to sum the observations over their balance sheet items in each period of time. Would that be possible in Stata?
>
>
> The dataset looks like that:
>
> Firm        Date    Item1    Item2    Item3
>
>
> Firm1     Date1   Item1    Item2    Item3
>
> Firm2      Date1   Item1     Item2    Item3
>
> Firm3      Date1  Item1    Item2     Item3
>
> ...so on.
>

If you want to add across item1-item3, then:

egen sum = rowtotal(Item1-Item3)

will do it. See -help egen-.

> I would like to merge in each period of time the data for firm 1 and firm 2 so the dataset will look like that:
>
>
> The dataset looks like that:
>
> Firm                  Date     Item1  Item2  Item3
>
>
> Merged_Firms    Date1  Item1  Item2  Item3
>
> Firm3               Date1  Item1  Item2  Item3
>

I think you are asking how to -collapse- just Firms 1 and 2 in each year of your dataset.  This example would need to be expanded to account for the total # of Firms you have in your data and how you want to -collapse- them, but it reproduces your example table above:

**********
clear
inp firm date item1
1 2007 45
2 2007 50
3 2007 99
end

g collapseind = 1 if inlist(firm, 1, 2)
replace collapseind = 0 if mi(collapseind)

collapse (sum) item1, by(collapseind date)
lab def x 0 "Firm 3" 1 "Merged Firms"
lab val collapseind x
li
**********

-Eric

__
Eric A. Booth
Public Policy Research Institute
Texas A&M University
[email protected]
+979.845.6754

> I would like to thank for your consideration in advance.
>
> Best,
>
>
> *
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> *   http://www.ats.ucla.edu/stat/stata/

*
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```

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