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...Concordant Uncertain 32.00000000 722.00000000 699.00000000 0.00000000 I.e., C=.968 instead of .963. But this is even farther away than the value from SAS you reported. If you don't believe the rcorr.cens result, create a tiny example and do the calculations by hand. Frank blackscorpio81 wrote > Dear R users, > > Please allow to me ask for your help. > I am currently using Frank Harrell Jr package "rms" to model ordinal > logistic regression with proportional odds. In order to assess model > predictive ability, C concordance index is displayed and eq...

Dear community, I'm currently attempting to predict the occurence of an event (factor) having more than 2 levels with several continuous predictors. The model being ordinal, I was waiting the glm function to return several intercepts, which is not the case when looking to my results (I only have one intercept). I finally managed to perform an ordinal polytomous logisitc regression with the

Dear community, I am currently trying to fit an ordinal logistic regression model with the polr function. I often get the same error message : "attempt to find suitable starting values failed", for example with : require(MASS) data(iris) polr(Species~Sepal.Length+Sepal.Width+Petal.Length+Petal.Width,iris) (I know the response variable Species should be nominal but I do as levels

In polr.R the (several) functions gmin and fmin contain the code > theta <- beta[pc + 1L:q] > gamm <- c(-100, cumsum(c(theta[1L], exp(theta[-1L]))), 100) That's bad. There's no reason to suppose beta[pc+1L] is larger than -100 or that the cumulative sum is smaller than 100. For practical datasets those assumptions are frequently violated, causing the

...UTC) From: Ben Bolker <[101]bbolker at gmail.com> To: [102]r-help at stat.math.ethz.ch Subject: Re: [R] glm - prediction of a factor with several levels Message-ID: <[103]loom.20100724T175114-259 at post.gmane.org> Content-Type: text/plain; charset=us-ascii blackscorpio <olivier.collignon <at> live.fr> writes: > I'm currently attempting to predict the occurence of an event (factor) > having more than 2 levels with several continuous predictors. The model > being ordinal, I was waiting the glm function to return several...

Dear community, I am currently attempting to perform a (L1) penalized ordinal logistic regression with proportional odds. For the moment I only found R packages allowing to perform forward or backward continuation ratio model with several penalizations. Does anyone have a clue of what R package I could use ? I am not even quite sure that penalized logistic regression with proportional odds has