1. A computer-implemented method for generating a defect sample for electron beam review, comprising: combining, on a defect-by-defect basis, one or more first attributes for defects determined by optical inspection of a wafer on which the defects were detected with one or more second attributes for the defects determined by optical review of the wafer thereby generating combined attributes for the defects, wherein the wafer is an unpatterned wafer; separating the defects into bins based on the combined attributes for the defects, wherein the bins correspond to different defect classifications; and sampling one or more of the defects for electron beam review based on the bins into which the defects have been separated thereby generating a defect sample for the electron beam review, wherein said combining, said separating, and said sampling are performed using a computer system.