Data indicative of a group of defect candidates may be obtained. The data may be indicative of a group of defect candidates and may include values of attributes for each defect candidate of the group of defect candidates. Sub-groups of defect candidates may be iteratively selected for review using a review recipe to classify the defect candidates in each selected sub-group based on the values of attributes of respective defect candidates and classification results of previously reviewed defect candidates. The sub-groups may be selected until a sampling stop condition is fulfilled to obtain a classification output for the wafer. Instructions specifying at least one of the sampling stop condition, the inspection recipe, or the review recipe may be altered and additional defect candidates in a next wafer may be classified by using the altered instructions.