The Addiction Severity Index (ASI) is an assessment tool that hs been used for several decades to assess largely self-reported data provided by patients. The target goal of the ASI is to determine through the screening and assessment processes how to best provide treatment for those with substance abuse issues. The ASI has been translated into multiple languages and modified for cultural and cultural-sensitivity concerns for use with a variety of demographic populations both in the U.S. and in countries around the world. The ASI was initially designed as a research tool, but in the years since it was first developed it has made its way into clinical settings and in other practical settings, and has become a common tool for screening and assessing patients with substance abuse issues. Numerous studies have been conducted to assess the validity of the ASI; such studies have largely demonstrated that the ASI is a reliable, flexible, and cost-effective assessment tool for screening patients and clients with substance abuse issues.