This corrigendum corrects an imprecision in the scoring formula presented in Recommendation ITU-T P.807 (02/2016), Section 6.4, for computing speech intelligibility scores adjusted for guessing. The current formula works correctly for two-alternative forced-choice tests (n=2) only. When applied to tests with more than two response alternatives, such as the Modified Rhyme Test (MRT; n=6), the formula significantly overcorrects for chance performance