[R] Specifying interactions in rms package... error

[David Winsemius]

On Aug 2, 2010, at 9:06 PM, Rob James wrote:

> model5 <- lrm( B_fainting ~   gender+  rcs(exactage, 7) +   
> rcs(DW_nadler_bv, 7) +           rcs(drawtimefrom8am, 7)+   
> DW_firsttime+   DW_race_eth +
> rcs(DW_BPS, 5)+  rcs(DW_BPD, 5)+  rcs(pulse3, 5)+  locat2+
> (rcs(exactage, 3) * rcs(drawtimefrom8am, 3))
>  )

The parentheses around the last two crossed rcs() terms are  
superfluous. I don't have experience that demonstrates that is the  
cause of the problem, but you might consider removing them anyway.

-- 
David Winsemius, MD
West Hartford, CT