Re: Deriving Formula from Ordinal Regression Results to Classify New Cases?

Posted by Ruben Geert van den Berg on Oct 24, 2012; 6:59am
URL: http://spssx-discussion.165.s1.nabble.com/Deciphering-from-t-test-the-mean-tp5715819p5715825.html

Dear Vik,

I guess if you figure out the structure of the formula (maybe "help" -> "algorithms" ?) we could insert the parameter estimates with Python (spssaux.GetValuesFromXMLWorkspace), thus completing your formula.

However, "if it ain't broken...". So what's the problem with the standard approach?

1) add the new cases to the old ones
2) compute a weight variable, 1 for old cases, close to 0 (e.g. 1e-12) for new ones
3) if necessary, compute a valid value on the dependent variable for new cases
4) weight cases by weight variable
5) run analysis and save predicted values

Including new cases in the analysis ensures they'll be given predicted values. However, the weighting procedure makes sure they won't have any effect on the parameter estimates (you'll see that these will be the same as for the old cases exclusively).

Best,

Ruben

> Date: Tue, 23 Oct 2012 20:30:29 -0700

> From: [hidden email]
> Subject: Deriving Formula from Ordinal Regression Results to Classify New Cases?
> To: [hidden email]
>
> What is the correct method for deriving a formula from the results of an Ordinal Regression, that can be used to predict the value of the dependent variable for new cases?
>
> Thanks very much in advance to all for any info.
>
> Best,
>
>
> -Vik
>
> =====================
> 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