Hi Listservers,
I have a dataset in long format which has dates when an individual visited a
doctor. I have another dataset with dates when that patient started taking a
medication. Naturally, the dates will not align exactly between the two data
sets.
Is there a way of merging the files so that the date when the patient
started taking the medication is aligned (put on the same line) to the
closest date (but after) of a given doctor visit?
Example
File 1 - office visits
ID date of visit
1 1/1/2009
1 1/31/2009
1 2/18/2009
1 3/14/2009
1 5/30/2009
1 7/12/2009
2 3/10/2009
2 4/25/2009
2 5/20/2009
3 2/09/2009
3 6/08/2009
3 7/10/2009
File 2 - medication fill date
ID date of first fill
1 2/22/2009
2 4/15/2009
3 7/15/2009
If I would like the medication date to be added to the office visit file to
be matched to the last closest office visit, then ID 1 medication date
should align with 1/31/2009, ID 2 should align with 3/10/2009 and ID 3
should align with 7/10/2009.
Thanks in advance
Ariel
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