In the use of optical answer sheet examinations, occasionally the identity of the examinee is in question. A novel method for characterizing the personal quality of mark shapes in optically read answer sheets is described. The method may be used to identify imposters in multiple choice examinations. All the marks are segmented and measured in multiple parameters including area, dimen- sions, perimeter and optical density. Imposter decisions are made on the collected data by comparing an identified test form against the form in question in comparison with a population using SVM (support vector machine) modeling