Citation

MacDonald IL, Lerer LB. Int. J. Epidemiol. 1994; 23(1): 66-72.

Affiliation

Department of Business Science, University of Cape Town, Rondebosch, South Africa.

Copyright

(Copyright © 1994, International Epidemiological Association, Publisher Oxford University Press)

DOI

unavailable

PMID

8194926

Abstract

In order to determine whether firearm use was an increasing component of the general pattern of homicide in Cape Town, South Africa, hidden Markov time-series models were used to examine a week-by-week count of firearm homicides, non-firearm homicides, firearm suicides and non-firearm suicides for the 6-year period from 1986 to 1991. Of several models fitted to the proportion of homicides that involved firearms, the one which incorporated a discrete upward shift in the middle of 1991 was the most successful. There was no evidence of a similar upward shift in the proportion of the suicides that involved firearms. The sharp increase in 1991 in the probability that a homicide involved the use of a firearm is consistent with a reported upsurge in violence related to the so-called 'taxi wars'. Hidden Markov models, as a general methodology for the analysis of discrete-valued time series, may be a useful and flexible means of identifying time trends or points of transition related to events or interventions in a wide range of public health contexts.