The first methods proposed for such inference are maximum likelihood procedures based upon chain-binomial models, such as the Reed-Frost model, or the stochastic formulation of the Kermack-McKendrick model considered by Bartlett [158] . These early methods are summarised by Bailey [126] . They, and the significant majority of methods proposed for household inference to date, use finalsize data which can be readily obtained from household serology results. A simplifying assumption to facilitate inference in most methods is that the epidemics within the various households evolve independently (e.g., see the martingale method of Becker [159] , which requires the duration of a latent period to be substantial for practical implementation).