The original Spectral Correlation Index (SCI[underscore o]) is a measure of amplitude envelope distortion that has been used in several studies to predict behavioral results. Because the original SCI[underscore o] did not account for the differential contribution of particular frequency bands to speech intelligibility (i.e., band importance) or for audibility, a new "individual" version (the SCI[underscore i]) is proposed and evaluated. Sentence intelligibility data are used to compare the predictive power and goodness-of-fit for statistical models using two versions of the SCI. The SCI[underscore i] provides significantly better fits to behavioral data than the SCI[underscore o]. This result demonstrates the importance of accounting for and including signal audibility in analyzing and modeling data collected from the population of individuals with hearing impairment. With this update, the SCI[underscore i] is a useful measure for predicting speech intelligibility based on amplitude envelope distortions.