Re: Weight of evidence (WOE)

Posted by Mike on Jan 05, 2012; 5:12pm
URL: http://spssx-discussion.165.s1.nabble.com/Weight-of-evidence-WOE-tp5122524p5123306.html

Weight of Evidence and Information Value are outside of my area
of expertise but, after checking several websites, it appears that
there might be something wrong with the equations provided below.
Here is a link to an example I found that goes into a fair amount
of detail on output generated by SAS; see:

http://www.focusoptimal.com/doc/Information-Value-Calculation-Continuous.pdf

I assume that there is someone on this list that is familiar with the
weight of evidence or a Bayesian who can properly interpret what
is going on -- such as in this example:
http://www.web-e.stat.vt.edu/vining/keying/weight_of_evidence.pdf

-Mike Palij
New York University
[hidden email]

On Thu, Jan 5, 2012 at 11:23 AM, David Marso <[hidden email]> wrote:

Not sure this helps considering
WOE= Ln(good)-Ln(goodtot(4004376)) -Ln(bad)+(Ln(badtot(75775))
is *NOT* a properly constructed mathematical expression!
Please fill in the specifics *WITH* the steps involved in calculation of the
value you believe WOE should evaluate to.


DEBOER wrote
>
> age               good      bad     tot          column%        outcome
> woe           infomationvalue
>
> 18-20           150355    4667  155022      4%          3%
> -0.4949        0.0119
>
> 21-41           2013941  46674  2060615    51%        2.3%
> -0.2027        0.0229
>
> 41+             1840080   24434  1864514    46%         1.3%
> 0.3542          0.0484
>
> tot               4004376   75775  4080151   100%        1.9%
> 0.0834
>
> Ok, We have a variabel age, I do a crosstab in spss with age and
> default(0=good and 1=bad).
> I get outcome from bad/tot
> WOE= Ln(good)-Ln(goodtot(4004376)) -Ln(bad)+(Ln(badtot(75775))
> Informationvalue= WOE*((good/goodtot)-(bad/badtot))
>


--
View this message in context: http://spssx-discussion.1045642.n5.nabble.com/Weight-of-evidence-WOE-tp5122524p5123145.html
Sent from the SPSSX Discussion mailing list archive at Nabble.com.

=====================
To manage your subscription to SPSSX-L, send a message to
[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
SIGNOFF SPSSX-L
For a list of commands to manage subscriptions, send the command
INFO REFCARD