About Turnbull's Statistic

Turnbull's method detects local spatial clusters in case and population-at-risk data. This method can be applied to point or polygon geographies. Previously, this method was only available for point geographies.

Populations within the study area are scanned for clusters of cases. A circular window is centered on each region in turn and expanded to include neighboring regions until the total aggregated population within the window equals a user-defined threshold. Then whether there are more cases in that population than would be expected by chance is evaluated using Monte Carlo randomizations.