Analysis of incomplete durations with application to contraceptive use

Models for analysing incomplete durations obtained from cross-sectional sur veys are presented. The aim of the paper is to develop a framework for anal ysing the incomplete duration of episodes in progress at the time of the su rvey by formulating generalized linear models and fitting and assessing the m by using standard statistical packages. The maximum quasi-likelihood meth od is used for model fitting. The choice of the distribution and the diagno stic procedures are discussed. Simulated data from two distributions (the W eibull and log-logistic distributions) are used to evaluate the methodology developed and to assess model misspecifications. A data set on the current use of the contraceptive pill from a cross-sectional survey in Egypt is an alysed.