Sexual Abuse: A Journal of Research and Treatment, Vol. 17, No. 4, October 2005 (
The Utility of Cumulative Meta-Analysis:
Application to Programs for Reducing
R. Karl Hanson
and Ian Broom
Recent advances in meta-analytic techniques provide a useful framework for in-
terpreting the ﬁndings of individual studies. Simple formula are presented for
determining whether the results of a single study are statistically different from the
cumulative average of previous studies, and for calculating the new cumulative
average. When applied to two controversial social policies (treatment of sexual of-
fenders; rape prevention programs for college women), cumulative meta-analyses
suggested patterns that were not identiﬁed by the authors of the individual studies
nor by narrative reviews of these content areas.
KEY WORDS: cumulative meta-analysis; sexual violence; rape prevention.
The need to integrate the ﬁndings from large numbers of research studies
has lead to the development of a new form of research—the meta-analysis, or
quantitative summary of individual ﬁndings. Quantitative summaries are not new,
dating back at least to Karl Pearson and Ronald Fisher (Olkin, 1995), but it
was Glass’ study of psychotherapy outcome (Glass, 1976; Smith & Glass, 1977)
that introduced the term “meta-analysis” and inspired social scientists eager for
improvements over the traditional narrative review (Hunt, 1997). After the ex-
pected criticisms and scrutiny, meta-analysis has become the accepted method
for answering questions concerning the magnitude and direction of empirical
relationships (Cooper, 2003).
Public Safety and Emergency Preparedness Canada, Ottawa, Ontario.
Carleton University, Ottawa, Ontario.
To whom correspondence should be addressed at Public Safety and Emergency Preparedness
Canada, 340 Laurier Avenue, West, Ottawa, Ontario, K1A 0P8 Canada; e-mail: Karl.Hanson@psepc-
2005 Springer Science+Business Media, Inc.