It is important to determine if switching from simultaneous to sequential lineups affects response bias (the inclination to make an identification from a lineup), discriminability (the ability to distinguish between innocent and guilty suspects), or both. Measures of probative value cannot provide such information; receiver operating characteristic analysis can. Recent receiver operating characteristic analyses indicate that switching to sequential lineups both induces more conservative responding and makes it more difficult to distinguish between innocent and guilty suspects. If more conservative responding is preferred (i.e., if policymakers judge that the harm associated with the reduction of correct identifications is exceeded by the benefit associated with the reduction in false identifications), recent data indicate that this result can be achieved without a loss of discriminability by using the simultaneous lineup procedure in conjunction with a more conservative decision criterion.