Correlated mortality risks of siblings in Kenya: death clustering and a model for analysis

Walter D. Omariba, McMaster University
Fernando Rajulton, University of Western Ontario

This paper uses the 1998 DHS to examine the correlation of siblings’ mortality risks in Kenya. Previously, the random-effect parameter in the random model has been interpreted in terms of unmeasured and unmeasurable factors, suggesting the presence of death clustering. This is essentially problematic because the concept of unobserved heterogeneity is not the same as death clustering. This paper attempts to clarify the concept of death clustering and demonstrates that the concept needs to be closely associated, and therefore examined, with the sequence of births and deaths in a family. Again, earlier approaches have been insensitive to sequencing both in the clarification of the concept and in the analytical methods used to examine the presence and extent of death clustering. Using binary sequence models that also incorporate unobserved heterogeneity, we show that the parameter for death clustering is conceptually distinct from the parameter one usually obtains for unobserved heterogeneity.