Semiparametric models for capture-recapture studies with covariates

A 4exible method for modelling capture–recapture data with continuous covariates that describe heterogeneous catchability is developed. The well established generalized additive modelling framework is used. An estimator of population size is developed using this method. The performance of the method is demonstrated using neural tube defect capture–recapture data from the Netherlands, with the birth weight of a child as a covariate. The parametric bootstrap is used for variance estimation. c © 2003 Elsevier B.V. All rights reserved.