1. A computer-implemented method for selecting one or more parameters for a defect detection method, comprising: acquiring information for a set of classified defects, wherein the classified defects were detected on a wafer using an inspection system, and wherein the classified defects comprise defects of interest and nuisance defects; acquiring an objective for a defect detection method, wherein the defect detection method is to be applied to output generated for wafers by one or more detectors of an inspection system to thereby detect defects on the wafers, and wherein the objective is specified by a user; and selecting two or more parameters of the defect detection method simultaneously using an optimization function and the information for the set of classified defects such that the two or more parameters satisfy the objective, wherein the optimization function is constrained by one or more ranges of values selected by the user for at least one of the two or more parameters, wherein said selecting comprises simultaneously considering multiple passes of data generated for the wafer against the objective to find a combination of the multiple passes that best meets the objective, simultaneously selecting one or more parameters for multiple defect detection algorithms performed in the defect detection method, and simultaneously selecting one or more parameters for multiple detection channels of the inspection system used in the defect detection method, wherein the one or more detectors are included in the multiple detection channels, and wherein acquiring the information, acquiring the objective, and said selecting are performed using a computer system.