Re: st: merge using interval data

[Richard Goldstein <richgold@ix.netcom.com>]

the reason not to do what Kit suggested is that there are multiple 
records/provider as there is a new contract at least once per year
(of course, I suppose that I could "fix up" the provider file and
then do this ....)

Rich

Kit Baum wrote:

> Rich wrote
>
>  > The issue: I have two data sets, one large (gigabytes) with
>  > individual data including a unique id and a date of occurrence
>  > of a service being provided.
>  >
>  > I need the status of the provider on the date of occurrence
>  > for each case.  I have a second data set that includes, for
>  > each provider their status as of a period of time (e.g.,
>  > a beginning and ending date for a contract).
>  >
>  > I need to merge the two so that the provider's status is
>  > included in the individual data set.
>  >
>  > The only solution I currently see involves expanding the
>  > provider data set so each possible data (from the beginning
>  > of the contract to the end) is covered and then merging the
>  > two data sets (using the nokeep option).  However, this
>  > strikes me as inefficient.
>  >
>
> I presume the individual dataset indicates which provider was involved 
> with the individual record. If so, why not just merge the two datasets 
> on provider, which should leave you with something like
>
> indivID  dateService providerID  providerStart ProviderEnd
>
> Then you can just generate status = ( providerStart <= dateService <= 
> ProviderEnd )
> and drop the start and end variables... (Yes, that is not a Stata 
> statement, but you know what I mean)
>
> Kit Baum, Boston College Economics
> http://ideas.repec.org/e/pba1.html
>
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