Group projects are widely used in higher education, but they can be problematic if all group members are given the same grade for a project to which they might not have contributed equally. Most scholars recommend addressing these problems by awarding individual grades, computing some kind of individual weighting factor (IWF) from peer and (sometimes) self-assessments, which is then multiplied by the group grade to generate an individual grade. Several variants of the IWF method have been proposed, sometimes with complex algorithms. However, theory suggests they are inaccurate and their accuracy has not been evaluated. This article uses Monte Carlo experiments to assess the accuracy of the original IWF method and variants proposed in the past decade. Findings show that the earlier, simpler methods work best and that self-assessments should definitely be avoided.