The Head Start Impact Study (HSIS) uses many instruments to collect data. This document provides a complete list of the HSIS instruments indexed in the Research Connections' database. Every instrument is hyperlinked to its corresponding record and "X"s designate which cohorts they were used in. Other alpha characters represent the instruments' availability: OS = obtainable through the original source; RC = obtainable through Research Connections. While all instruments are listed, those instruments that are copyrighted are not available. To access a particular instrument, click on the appropriate link.