Abstract: A computerized method for categorizing defects on a substrate. A list of defects on the substrate is received as input to a processor, where each defect is represented by a defect location and an associated micro-defect code. The input is analyzed with the processor to detect spatial clusters of defects on the substrate. The spatial clusters are analyzed with the processor to determine which of the spatial clusters represent known macro-defects and which of the spatial clusters represent unknown macro-defects. The micro-defect code associated with each defect that is included in one of the spatial clusters that is determined to be a known macro-defect is changed with the processor with a macro-defect code that is associated solely with the known macro-defect. The processor analyzes the defects that are included in one of the spatial clusters that is determined to be an unknown macro-defect to determine a predominantly occurring micro-defect code.