[R] GLM: What is a good way for dealing with new factor levels in the test set?

Jim Lemon drjimlemon at gmail.com
Thu Apr 30 08:54:34 CEST 2015

Hi thuksu,
Would defining the factor in your training set with all the levels
that occur in the test set solve the problem? That is, there would be
at least one factor level in the training set even though there were
no instances of that factor.


On Thu, Apr 30, 2015 at 8:05 AM, thuksu <toby at huksu.com> wrote:
> My training set and my test set have some factor levels that are
> different....  It's rare, but it occurs.
> What is a good way for dealing with this?
> I don't want to throw away the entire row from the data frame, because there
> is some valuable information in there.
> Is there some way to say something like "use the weighted average
> coefficient level for this factor"?
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