g********3
发帖数: 123 | 1 when I use proc logistic......;class......;model....../selection=stepwise;
run; I got the warning:
WARNING: Ridging has failed to improve the loglikelihood in Step 1. You may
want to increase the
initial ridge value (RIDGEINIT= option), or use a different ridging
technique (RIDGING=
option), or switch to using linesearch to reduce the step size (
RIDGING=NONE), or
specify a new set of initial estimates (INEST= option).
WARNING: The LOGISTIC procedure continues in spite of the above warning.
Results shown are based
on the last maximum likelihood iteration. Validity of the model fit
is questionable
Then I add '/param=ref', the warning goes away although it shows in the
stepwise selection output. I wonder how to solve this problem first, and
then what does dummy variable creation affects my model fitting?
Thanks! | r*****y
发帖数: 199 | 2 Maybe you should try exact logistic regression. Some cell counts are too
small in your data. Therefore you have a converge problem utilizing maximal
likelihood estimation. |
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