1. A data analysis system for semiconductor test data, comprising a computer system, wherein the computer system is configured to operate: a local outlier identification system configured to: select a data subset from the semiconductor test data corresponding to a spatially-related subgroup of components on a substrate, wherein the spatially-related subgroup of components comprises a group of adjacent components within an area defined on the substrate that is fewer than all of the components on the substrate; and automatically identify a local outliers in the data subset, wherein the local outlier comprises an outlier relative to the selected data subset.