Modelling carryover for more complex designs.



Stephen Senn
University College, London


Abstract: Some brilliant mathematical investigations have been caried out into optimal cross-over designs. Unfortunately, however, the models employed have been biologically innocent: it has ben assumed that carry-over depends on the previous treatment only and lasts for one period. This implies that steady state is reached by the end of two periods. When biologically experienced modelling is used it can be seen very easily that so-called 'optimal' designs are not. This talk will give a very simple demonstration of the point.