VioLit summary: OBJECTIVE: The aim of this study by Centerwall was to evaluate television as a risk factor for violence by examining homicide rates in South Africa, Canada and United States. METHODOLOGY: The author followed a quasi-experimental design in which homicide rates in Canada and United States were compared retrospectively with those of South Africa. From an epidemiological orientation, author sought to determine effect of an intervention, introduction of television, on homicide rates by using as a control group a population which was not subjected to intervention. In Canada and United States television was introduced in 1945 while in South Africa, television was not introduced until 1974. South Africa was selected as control population since it did not receive intervention, television, until almost thirty years after Canada and United States. The author compared only homicide rates of white populations of each country. FINDINGS/DISCUSSION: The author found that between 1945 and 1974 annual incidence of white homicide deaths in United States and Canada increased 93 per cent and 92 per cent, respectively. In United States, there were 3.0 homicides per 100,000 whites in 1945 compared with 5.8 homicides per 100,000 in 1974. In Canada, there were 1.3 homicides per 100,000 in 1945 compared with 2.5 homicides per 100,000 whites in 1974. The incidence of white homicide deaths in South Africa during this same time period decreased by 7 per cent; there were 2.7 homicides per 100,000 whites in 1943-1948 compared with 2.5 homicides per 100,000 in 1974. Since violence is a multifactor phenomenon involving many variables, author suggested that attained rate of violence reflects exposure to television, particular country's baseline rate of violence, as well as effect of changes in other risk factors, such as socioeconomic conditions. The author further argued that this type of population intervention study is free of ecological fallacy. The ecological fallacy occurs when investigator infers that unobserved effect of one variable on another at level is same as observed effect at group level. In present study, author suggested that issue of ecological fallacy is rendered moot insofar as the link between risk factor and outcome variable has already been established at level of individual (p. 646). Each white South African was equally without television in same way as each white Canadian and American was with television between 1945 and 1974. The author also acknowledged that in conducting this type of comparative study there are rough edges insofar as prior to 1975 there could have been South African whites who were exposed to television outside of South Africa. Specification bias was reduced by choosing a control population, South Africa, with a similar social and historical background to Canada and United States. The author examined potentially confounding third variables, but found none adequately explained observed homicide trends. Potential confounding third variables were controlled through use of multiple control groups. However, author was unable to control for effect of local inaccessible confounders since there were no other television-free countries similar to South Africa. The author found that two major etiologic hypotheses were substantiated by data. One hypothesis stated that exposure to television is followed by an increase in rates of violence. Another hypothesis stated that timing of introduction of television predicts timing of subsequent increase in rates of violence. In conclusion, author calculated that exposure to television is etiologically related to about one half of homicides committed in United States. EVALUATION: The author presents an interesting comparison of homicide rates in United States, Canada and South Africa as a function of each countries' relative exposure to television. However, task of explaining an entire country's rate of homicide by exposure to television alone seems problematic for several reasons. The author does not convincingly justify exclusion of effects from other confounding variables from relationship. For example, relative effects of exposure to other mediums in each country is not discussed. Finally, author assumes that backgrounds of all three countries are comparable and that there was similar television programming both in Canada and United States during period studied. (CSPV Abstract - Copyright © 1992-2007 by Center for Study and Prevention of Violence, Institute of Behavioral Science, Regents of University of Colorado) N1 - Call Number: F-433, AB-433 KW - South Africa KW - Canada KW - US Foreign Comparison KW - Countries Other Than USA KW - Homicide Rates KW - Television Viewing KW - Television Violence KW - Comparative Analysis KW - Violence Risk Factors KW - Violence Causes KW - Media Violence Effects KW - Caucasian Adult KW - Caucasian Victim KW - Adult Victim KW - Cross National Comparison KW - Cross National Differences KW - 1940s KW - 1950s KW - 1960s KW - 1970s