Dear Tate, If I understand correctly what you're asking, the formulas are on p. 21 of the paper at <http://socserv.socsci.mcmaster.ca/jfox/Papers/logit-effect-displays.pdf>. But why do you want to do this when you can get the fitted probabilities from predict()?
I hope this helps. John -------------------------------- John Fox Department of Sociology McMaster University Hamilton, Ontario Canada L8S 4M4 905-525-9140x23604 http://socserv.mcmaster.ca/jfox -------------------------------- > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Tate Avery > Sent: Friday, August 12, 2005 2:50 PM > To: r-help@stat.math.ethz.ch > Subject: [R] Manually Calculating Odds from POLR Model > > Hello, > > I am using polr(...) to generate a model. The summary shows > the coefficients and the intercepts. > > For example: > > coefficient for x1 = c1 > coefficient for x2 = c2 > > intercept A|B = i1 > intercept B|C = i2 > > I can then run predict(..., type="p") with the model and see > the odds for each factor. > > For example: > > A B C > 1 0.3 0.5 0.2 > 2 0.4 0.1 0.5 > > What I really want to be able to do is take the 2 > coefficients, the 2 intercepts, the x1 & x2 values and > manually calculate the probabilities generated by predict(). > > I have been searching quite extensively for the underlying > calculations that transform the polr output and the input > variables into the final output odds. I have tried a number > of dead-end roads so far. > > So, if anyone has any information on how to do this or where > I can find out, I would be extremely grateful. > > Thank you for your time, > Tate Avery > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html