what does "Lowest coded group" mean in reference to categorical variables in multiple logistic regression

General
1

Hi everyone,

I have been reading up on the use of categorical variables in multiple logistic regression and have come across phrases like this one a couple of times stating that for categorical variables the coefficients give log odds for each categories effect on the variable of interest relative to the reference category and that in r the default is that the "reference group is the lowest coded group" , but I am having a hard time figuring out what is meant by the lowest coded group? Thanks so much for any insight.

2

Is it just as simple as that each level in the factor data is assigned a number and that reference number is the code that is being referred to? Thanks

3

The lowest coded group is the first one in the list of levels in the factor. It is stored with the value 1. The default ordering is alphabetical.

4

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