Date:         Sat, 20 May 2000 01:24:30 +0100
Reply-To:     John Whittington <John.W@MEDISCIENCE.CO.UK>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         John Whittington <John.W@MEDISCIENCE.CO.UK>
Subject:      Re: replacing missing values with *next* value
Comments: To: sashole@mediaone.net
In-Reply-To:  <200005192335.AAA01525@vicar.netnames.net>
Content-Type: text/plain; charset="us-ascii"

At 23:34 19/05/00 GMT, Paul Dorfman wrote (in part):

>The intention below (which is, in essense, is a modified idea of looking 1
>record ahead from Ian Whitlock's SUGI 25 'SAS-L' paper) is to match the file
>by UID with its own copy where the first record in each by-group is
>exterminated. This way, each group starts from its second record, thereby
>providing a look-ahead mechanism:

Paul, although Jeremy was not explicit on this point, I presume that UID
relates to the mother, and that a given mother could have more than one set
of twins - in which case I don't think that 'exterminating' just the first
record for each (UID) BY group would necessarily always be enough.

However, it does seem that Pete Lund has 'thought laterally' and has come
up with a way of using LAST.DOB to effectively 'provide a look-ahead
mechanism', which appears very clever!

Kind Regards


John

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