Date: Wed, 14 Nov 2007 12:03:33 -0500
Reply-To: Richard Ristow <wrristow@mindspring.com>
Sender: "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From: Richard Ristow <wrristow@mindspring.com>
Subject: Re: CASESTOVARS with a VARS limit
In-Reply-To: <000b01c826d1$13a88250$3af986f0$@com>
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At 10:14 AM 11/14/2007, ViAnn Beadle wrote:
>The simple RFM analysis requires the unit of analysis be a giver and
>not a gift so you can aggregate the sum of gifts by user, get the
>max of date for the most recent date, and get the number within
>aggregate. Then use the Rank procedure to get your quintiles or whatever.
That is how I would expect to go about it. (As for details, I'm
little enough familiar with RFM analysis that I had to look up what it was.)
>WRT to looking at patterns, I think you want your record to be a
>giver containing pairs of variables for each gift (date and amount).
>You can get there via CASESTOVARS. You'll probably want to change
>the dates to offsets from the 1st date so that you can then compare
>givers. Once you have this, you can then find things like the mean
>number of gifts per user, mean number of days between gifts, etc.
I'm not sure that'S what I'd expect to do. I'd think first of leaving
data in 'long' form - one record per gift, many records per ID - and
calculating such statistics across the groups of records, mostly with
AGGREGATE. It would be quite easy to get,
Date and size of the most recent gift
Total number of gifts, and total amounts given, over various
stretches of time: in the past year, the past five years, the five
years before that, ...
With a little ingenuity, you can get quite a set of such measures in
a single AGGREGATE run.
>So, I think you're right to be thinking about using CASESTOVARS for
>parts of this analysis after you select out really old gifts.
I'll be interested to see what techniques do turn out to serve you best.
-Good luck,
Richard
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