DM: Re: your mail

[Dan Steinberg]

In response to your modeling question below:

        (a) you will need to divide BOTH your active customers and
churners into train and test partitions
        (b) you might wish to use a decision tree to help you select 
your
inputs (CARTŪ (tm), C4.5, etc)

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 | Dan Steinberg             | FAX (619) 543 8888              |
 | Salford Systems           | VOICE (619) 543-8880            |
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on Thu, 9 Apr 1998, Hallberg Rassy wrote:

> Date: Thu, 09 Apr 1998 03:22:55 PDT
> From: Hallberg Rassy <hr38@hotmail.com>
> To: datamine-l@nautilus-sys.com
> 
> Dear Friend
> 
> I have now a problem and would like to share with you and to 
>receive, if 
> possible your opinion.
> Hereinafter the picture of situation:
> 1.I'm presently involved in a customer profiling project for a 
>large 
> mobile operator.
> 2.The goal is to set up a system able to anticipate the likelyhood 
>of 
> churn of  customers
> 3.As a pilot step I extracted call records for 10000 active 
>customers 
> plus 4000  churned
> 4.Using SPSS neural connection I made up a neural network based on 
>a set 
> of 4000  active+4000 churned
> 5.The data was: calling patterns of july, agoust and september the 
> target was:  churn/no churn situation in december
> 6.The results was promising: 90% of real churn anticipated, with a 
> cut-off  probability of 80%
> 7.The same network was used on october, nov, dec. data to 
>anticipate 
> march churn  the results dropped to a terrific 11% with the same 
>cut-off 
> of 80%: totally  useless
> 
> 
> I have formulated some hypotheses
> A.The low time span (three month) is affected by seasonality
> B.The data used are not sufficient to build a reliable network
> C.The tool (SPSS Neural Connection) is not reliable
> 
> Could you give your opinion?
> Many thanks in advance
> 
> 
 *---------------------------+---------------------------------*
 | Dan Steinberg             | FAX (619) 543 8888              |
 | Salford Systems           | VOICE (619) 543-8880            |
 | 8880 Rio San Diego Dr     |                                 | 
 | San Diego, CA 92120       | http://www.salford-systems.com  |
 *-------------------------------------------------------------*