Re: [R] interpreting bootstrap corrected slope [rms package]

2011-10-24 Thread apeer
I'm not implying they should be discarded; however, at the same time I'm not certain I fully understand why we should check the ordinality assumption if in the end we're going to include predictors with which the response variable behaves in a non-ordinal fashion. -- View this message in context:

Re: [R] interpreting bootstrap corrected slope [rms package]

2011-10-24 Thread apeer
One last thing. At the outset of this discussion I provided the results of a validation procedure on a model (see below). As discussed previously, the model overall seems to fair well, with the exception of the slope. With that in mind, is there a way to correct the coefficients of the model to

Re: [R] interpreting bootstrap corrected slope [rms package]

2011-10-23 Thread apeer
Dr. Harrell, Thanks for your response. The predictor variables I initially included in the model were based on the x mean plots and whether they exhibited ordinality and whether they appeared to meet the CR assumptions. Only 7 of 16 potential variables fit that designation and those are the

Re: [R] interpreting bootstrap corrected slope [rms package]

2011-10-23 Thread apeer
I guess I must be misunderstanding the point of checking the ordinality assumptions prior to fitting a model. Are you saying that a response variable that does not behave in an ordinal fashion can still be included in the initial and final model? -- View this message in context:

Re: [R] interpreting bootstrap corrected slope [rms package]

2011-10-23 Thread apeer
Does your point about proportionality also hold for ordinality? In other words, if I have several X variables that do not behave in an ordinal fashion with Y, should I still include them in the full model? My understanding or perhaps misunderstanding of the ordinality assumption was that all X

[R] cr.setup predict with se.fit

2011-04-19 Thread apeer
Hello, I've recently started using the rms package to fit some continuation ratio models using cr.setup. The package runs beautifully and I'm getting good fits with my data, however, I'm having trouble getting plots of the predicted mean values of y in relation to predictor variables with