st: Re: Size matching

["Michael Blasnik" <michael.blasnik@verizon.net>]

You may be able to use -nearmrg- to help with this.  Type -ssc describe 
nearmrg-   You would need to deal with tied values of BookValue in the 
Non-event firms table since -nearmrg- requires the merging value to be 
unique in the lookup dataset, but you would need to deal with ties in any 
approach you selected.

Michael Blasnik
(author of nearmrg)

----- Original Message ----- 
From: "Ingo Brooks" <ingo.brooks@gmail.com>
To: <statalist@hsphsun2.harvard.edu>
Sent: Wednesday, February 07, 2007 3:45 AM
Subject: st: Size matching



> Dear all,
>
> I have two datasets with yearly firm data. Sample 1 is the dataset
> containing the event firms (Initial public offerings (IPO) and
> seasoned public offerings (SEO)) and sample 2 contains the non-event
> firms (i.e. all firms which did not have an IPO or SEO in the last
> five years).
>
> The datasets are structured as follows:
>
> Dataset 1: Event firms
>
> ID        Year       BookValue      E_Ret
> E1        1995          670           12
> E2        1995          380           -8
> E3        1995         1120           -4
> E1        1996          682            9
> E3        1996         1120           -2
>
>
> Dataset 2: Non-event firms
>
> M_ID     M_Year     M_BookValue     M_Ret
> M1        1995          350           13
> M2        1995          430           12
> M3        1995          690            8
> M4        1995          890           -2
> M5        1995         1200           11
> M1        1996          350             8
> M2        1996          430            6
> M3        1996          690           -5
> M4        1996          890            4
> M5        1996         1200           10
>
>
> What I now would like to do is to match the Non-event firms with the
> event firms. In doing so, I would like to match the firms by aid of
> variable "BookValue". Specifically, I would like to obtain for each
> event firm the non-event firm whose BookValue is closest to but bigger
> than that of the event firm. As a result, I should obtain the
> following dataset:
>
>
> Dataset Final: Matched firms
>
> ID     Year    BookValue     ERet     M_ID    M_BookValue      MRet
> E1     1995       670         12        M3         690            8
> E2     1995       380         -8       M2         430           12
> E3     1995      1120         -4       M5        1200           11
> E1     1996       682          9       M3         690           -5
> E3     1996      1120         -2       M5        1200           10
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