Variation in the variable being analyzed with the Hot Spot Analysis Tool

Discussion created by flawson on Jun 13, 2011
Latest reply on Jun 14, 2011 by lrosenshein-esristaff
In ArcGIS 10's help under Hot Spot Analysis, it says: "The Input Field should contain a variety of values. The math for this statistic requires some variation in the variable being analyzed; it cannot solve if all input values are 1, for example. If you want to use this tool to analyze the spatial pattern of incident data, consider aggregating your incident data."

My question is how much variation is needed? I want to identify clusters of incidents using a point dataset, but the majority of my points (about 90%) only have 1 incident. If I don't aggregate, how will this impact my results? If I should aggregate the points (e.g., using a fishet grid), how much variation should I be aiming for?

Thank you for any help/suggestions!