Existing methods of indexing the vocational activities of adults with autism spectrum disorders (ASD) have made significant contributions to research. Nonetheless, they are limited by problems with sensitivity and reliability. We developed an index of vocational and educational outcomes that captures the full range of activities experienced by adults with ASD, and that can be reliably coded across studies using specific decision rules. To develop this index, we used employment, vocational, and educational data collected from nearly 350 adults with ASD at 6 times over 12 years, as part of a larger longitudinal study. The resulting index consists of 11 categories coded on a 9-point scale, ranging from competitive employment and/or postsecondary educational program to no vocational/educational activities. (Contains 3 tables.)