
4
Sequential and simultaneous
exposure–response modeling
In the last chapter we a ssumed that expo sures ar e availa ble wherever needed
in the ER model and can be used in the model directly. Here we focus o n
other situations when expo sures in the ER model are not directly available
and have to be estimated. Two main approaches under these situations are
known as sequential and simultaneous modeling in pharmacometrics, and two-
stage and joint modeling in statistics, although in most cases there is no exact
correspo ndenc e between these methods in the two fields.
4.1 Joint models for exposure and response
In the previous chapter we introduced the following ...