These cluster detection methods evaluate whether cases of a disease tend to aggregate in particular locations. Besag and Newell (1991) classified cluster detection methods into "general" and "focused" tests. We further subdivide "general" methods into "local" and "global" categories. For retrospective surveillance of spatial data, use Rogerson's Method.
General methods explore clustering without pre-determined hypotheses about cluster location.
Global methods detect clustering throughout the study area regardless of their specific locations or spatial extent.
Local methods detect clustering limited to geographically restricted areas within the study.
Focused methods detect clustering around a specific location, such as a point source exposure to a proposed risk factor.
