In the conviction of Lucia de Berk an important role was played by a simple
hypergeometric model, used by the expert consulted by the court, which produced
very small probabilities of occurrences of certain numbers of incidents. We
want to draw attention to the fact that, if we take into account the variation
among nurses in incidents they experience during their shifts, these
probabilities can become considerably larger. This points to the danger of
using an oversimplified discrete probability model in these circumstances.