Besag and Newell's r

The Besag and Newell's method calculates two statistics:  l, and r.  The global statistic, r, is the total number of clusters found in the local-scale analysis.

To get the observed r, SpaceStat counts the significant local clusters.

Assessing the p-value

SpaceStat evaluates r by comparing it to Monte Carlo randomizations of the geography. SpaceStat generates a reference distribution to evaluate r by repeatedly randomizing the data and recalculating r for each randomization. The data are randomized by drawing from a Poisson distribution with the expected value being the average rate for the dataset multiplied by the population in the cluster.