The modelling of correlated binary outcomes, in such a way that the ma
rginal response probabilities are still logistic, is considered. Diffe
rent association measures for the dependence between correlated observ
ations are discussed. For paired correlated data the full likelihood c
an be evaluated; for an arbitrary number of correlated observations a
pseudolikelihood approach to obtain parameter estimates is proposed. T
he results are illustrated on data from a Dutch follow-up study on pre
term infants.