227Formulating the Required Equations
time, but no information is given on what the determinants of the underlying
hazard function might be. Thus, the impact of determinants of interest like
patient characteristics and, possibly, even the effects of treatments of inter-
est, have to be taken from a different source. That alternate source may be a
study that reports a regression analysis that incorporates the determinants
of interest, often a Cox proportional hazards regression equation. Frequently,
however, the regression equation is derived from a study with a different
follow-up time. The following sections address these kinds of situations.
6.6.1 Incorporating External Data on Intervention Effects
A simple illustration of a situation requ ...