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From |
"Fabian Schönenberger" <sch.f@gmx.ch> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: RE: merge |

Date |
Fri, 01 Jun 2012 18:07:42 +0200 |

Yes I do! There is a variable called datadate with dates like ddmmyyyy, as well as one variable with dates like datemonthly with dates like yyyymXX. The date-variable I use to uniquely identify the observations is called year with yyyy. Should I drop the other ones? -------- Original-Nachricht -------- > Datum: Fri, 1 Jun 2012 08:19:49 -0700 > Von: Nick Sanders <sandersn@stanford.edu> > An: "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> > Betreff: Re: st: RE: merge > Fabian, > > As a shot in the dark, do you have any other variables that are common > among the two data sets? For example, if data set 1 and 2 both contain a > variable called "date" (in addition to the common variables on which you are > merging), merging those two data sets will sometimes make your results look > odd due to how Stata handles what to do with that variable. > > Best, > Nick > > > > On Jun 1, 2012, at 8:05 AM, Simon Falck <simon.falck@abe.kth.se> wrote: > > > Dear Fabian, > > > > It is difficult to give a specific reply when you do not tell us more > about your datasets and key variables. However, here are some general inputs > on merging files in Stata that perhaps are useful for you. > > > > The -merge- command enables merging files with common id´s. One-to-one > -merge 1:1- implies that the identifiers (key variables) are exactly the > same in both files. If this is not your case then you should consider > Many-to-one -merge m:1- or One-to-many -merge 1:m-. It depends on how your > datasets are structured and their content. The two latter options are used when > you have a common id in both files and one file, either the master or user, > differ in for example time period. If you have two datasets which includes > id´s that are non-common in both directions you use the Many-to-many > -merge m:m- option. > > > > As understood the key-variables are important to inspect according to > the options described above. Don’t forget to inspect the format, for > example are both key variables in string format? Consider how a key-variables > should be constructed and what a common attribute implies and the directions. > > > > You get a great instruction by typing: -help merge- > > > > Good luck, > > Simon > > > > > > > > -----Original Message----- > > From: owner-statalist@hsphsun2.harvard.edu > [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of "Fabian Schönenberger" > > Sent: den 1 juni 2012 14:28 > > To: statalist@hsphsun2.harvard.edu > > Subject: st: merge > > > > Dear Statalist > > I try to merge two datasets. In both files each observation is uniquely > identified by cusip and year. I sort both files with xtset cusip year. > Afterwards, I command: > > > > merge 1:1 cusip year using "C:\Users\User\Documents\Uni > SG\Doktorat\Data\Price Data\pricedatev5.dta", keepusing(capm_marketpremium), keep(3) > > > > I am only interested in those observations of cusip-year-combinations > which are in my masterfile - therefore keep(3). > > > > However, either the matched observations nor the unmatched observations > are correct, meaning that I get for each cusip-year observations the wrong > capm_marketpremium and I do not get observations in my masterfile for > cusip-year observations although the using file has an observation. > > > > I also tried merge m:m but it did not work. What am I doing the wrong > way? > > > > Many thanks for suggestions. > > > > Fabian > > -- > > NEU: FreePhone 3-fach-Flat mit kostenlosem Smartphone! > > > Jetzt informieren: http://mobile.1und1.de/?ac=OM.PW.PW003K20328T7073a > > * > > * For searches and help try: > > * http://www.stata.com/help.cgi?search > > * http://www.stata.com/support/statalist/faq > > * http://www.ats.ucla.edu/stat/stata/ > > > > * > > * For searches and help try: > > * http://www.stata.com/help.cgi?search > > * http://www.stata.com/support/statalist/faq > > * http://www.ats.ucla.edu/stat/stata/ > > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ -- NEU: FreePhone 3-fach-Flat mit kostenlosem Smartphone! Jetzt informieren: http://mobile.1und1.de/?ac=OM.PW.PW003K20328T7073a * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: RE: merge***From:*Nick Sanders <sandersn@stanford.edu>

**References**:**st: merge***From:*"Fabian Schönenberger" <sch.f@gmx.ch>

**st: RE: merge***From:*Simon Falck <simon.falck@abe.kth.se>

**Re: st: RE: merge***From:*Nick Sanders <sandersn@stanford.edu>

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