. "A Using Disease Cluster and Small-Area Analyses to Study
Environmental Justice." Toward Environmental Justice: Research,
Education, and Health Policy Needs. Washington, DC: The National
Academies Press, 1999. The following HTML text is provided to
enhance online readability. Many aspects of typography translate
only awkwardly to HTML. Please use the page image as the
authoritative form to ensure accuracy. What Type of Summary
Statistic is Used? Two main statistical approaches are used by
cluster methods. In one, distances between all pairs of events
(case-case, case-control, case-exposure, etc.) are calculated
and summarized. These may be summarized as the number of case
pairs closer than a certain separation distance, such as the
mean distance between cases or such as the mean distance of each
case to the nearest other case. On the other hand, the whole
distribution of distances may be used. If controls are used,
then a summary of the case distances may be compared to a
summary of the control distances or