simple interactions
I was right that there is an easy answer! Thanks for the 3 quick answers, all three correct and useful. Terry Therneau
On 04/15/2016 07:15 AM, Thierry Onkelinx wrote:
Dear Terry, Does fitting group + age:group instead of age*group solves your problem? Best regards, ir. Thierry Onkelinx
2016-04-15 13:58 GMT+02:00 Therneau, Terry M., Ph.D. <therneau at mayo.edu
<mailto:therneau at mayo.edu>>:
I'd like to get interaction terms in a model to be in another form. Namely, suppose I
had variables age and group, the latter a factor with levels A, B, C, with age *
group in the model. What I would like are the variables "age:group=A", "age:group=B"
and "age:group=C" (and group itself of course). The coefficients of the model will
then be the age effect in group A, the age effect in group B and the age effect in C
rather than the standard ones of an overall age effect followed by contrasts. These
is often a better format for tables in a publication.
Yes, I can reconstruct these from the original fit, but I have a lot of variables for
several models and it would be easier to have an automatic form. I suspect that there
is an easy answer, but I don't see it.
Terry Therneau