st: handling dates to find latest date from multiple records

[Sunday Clark <sunday.clark@gmail.com>]

Dear Statalist,

I am using Stata 12.0. I have a dataset of hospitalized patients with
hospital stays ranging from 1-30 days. There is a daily data
collection form that was supposed to be filled out each day of the
hospitalization for each patient. For most questions on the form,
there should be a response on each day. Another part of this form asks
for the date that the doctor thinks the patient is better, the date
the patient thinks the patient is better, and the date the doctor
thinks the patient can safely be discharged. This is all supposed to
be answered on the daily form on the last day of the hospitalization,
but the individual questions were sometimes answered on the day that
the individual criterion was met. I would like to be able to identify
each of these dates and the date on which all three were met, if they
were met on different dates. Can anyone provide me with suggestions
for how to do this in an efficient manner? I have the data in long and
wide format.

In long format it looks like the following:

subjectid	IPF_record	totalIPFs	IPF_ID	IPFQ1	IPFQ2	IPFQ3
1	1	1	9	11/07/05	11/08/05	11/07/05
2	2	2	58	01/24/06	01/24/06	01/24/06
2	1	2	57	.	.	.
3	1	1	6	01/07/06	01/08/06	01/08/06
4	1	1	10	11/08/05	.	11/08/05
5	2	2	12	11/13/05	11/13/05	11/14/05
5	1	2	11	11/13/05	11/13/05	11/13/05
6	1	1	37	11/27/05	11/27/05	.
7	1	1	38	12/04/05	.	12/03/05
8	8	8	46	12/10/05	.	12/10/05
8	6	8	44	.	.	.
8	4	8	42	.	.	.
8	7	8	45	12/10/05	.	12/10/05
8	3	8	41	.	.	.
8	1	8	39	.	.	.
8	2	8	40	.	.	.
8	5	8	43	.	.	.


Thank you in advance,
Sunday
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