Hello STATAlisters -
The question that follows is part STATA and part statistical
technique. Suppose I have a continuous independent variable in
a logistic (or cox) model and I wish to reconfigure the
variable as a categorical (read ordinal) variable so that the
odds ratio (hazard ratio) will be more meaningful, but before I
categorize the variable and insert it into the model I'd like
to determine whether the categories (e.g hospital volume: low,
medium, high) are monotonic relative to the outcome (e.g. shunt
survival as measured in fractions of years) so as to establish
some justification of linearity. If "monotonicity" cannot be
determined, then I understand that indicator variables must be
created and odds ratios (hazard ratios) returned are relative
to a referent group. My question is two-fold: is this an
acceptable technique and if so, is there a straightforward and
acceptable way to proceed using STATA??
Many thanks in advance!
Clint Thompson
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