CODEWITHSUNDEEP
saslogistic-regression
Uttara
Uttara

Reputation: 125

Logistic regression reference coding in SAS

I'm doing multiple logistic regression in SAS. One of the independent variables has 10 different events (0 to 9) and 0 is directly related to the dependent variable being positive. Now, if I code so that ref = '0', none of the other events under this independent variable are statistically significant; whereas if I code so that my ref is something other than 0, almost all the events are significant. Needless to say, the model is changing significantly in both these cases, but the sensitivity, specificity, false POS, and false NEG are staying the same. Any help as to which way is correct is much appreciated.

Upvotes: 1

Views: 222

Answers (1)

DanZ
DanZ

Reputation: 481

It doesn't really matter what you're reference groups is, the overall model will be the same.

The only thing that will change is how your word your explanation of an effect relative to your reference group.

Here are some articles that might help:

http://www.theanalysisfactor.com/strategies-dummy-coding/ http://www.theanalysisfactor.com/when-dummy-codes-are-backwards/

Upvotes: 1

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