A method for production line monitoring during semiconductor device fabrication includes acquiring a plurality of inspection results from a plurality of reference samples with an inspection sub-system. The method includes storing the acquired inspection results and geometric pattern codes for each of the reference samples in a database. The method includes acquiring an additional inspection result from an additional sample, where the additional inspection result includes an additional set of geometric pattern codes for identifying each defect identified within the additional inspection result from the additional sample. The method also includes correlating the set of geometric pattern codes of the additional sample with the geometric pattern codes from the reference set of samples to identify at least one of one or more new patterns or one or more patterns displaying a frequency of occurrence above a selected threshold.