Questions of a Novice in Latent Markov Modelling

Change is the main issue when panel data are collected. This paper focuses on latent class analysis as a means to represent the regularities in such repeated measurements of the same objects. It does so without adding any novelty to the extensive methodological literature. The emphasis is rather on facilitating the application of these methods. We will elaborate on the questions of a student (Mannan, 2001) who recently finalised a paper on smoking behaviour that relies heavily on latent class analysis. Before addressing these questions, an overview of the uses of latent class analysis will be given in the next section, followed by a brief introduction to the general model that is used by Mannan for the analysis of his panel data. This model is at the basis of the computer program PANMARK, which the first author developed in collaboration with Rolf Langeheine. In fact, the present paper is written at the occasion of his retirement. And that is a good reason for writing a paper, because the many quotations of his work by various authors show that the views of Rolf Langeheine have shaped the methods for categorical data in discrete time.