A large study of classrooms in the Caribbean context necessitated the use of a validated classroom observation tool. In practice, the paper-version Stalling's instrument (Stallings & Kaskowitz 1974) presented specific challenges with respect to (a) facile data collection and (b) qualitative observations of classrooms. In response to these shortfalls, the Stalling's classroom observation tool has since been modified and supplemented with qualitative observation scales. In an effort to promote efficiency of observation and data collection, the tool has been reconfigured as an iPad® application. The research described herein used four independent studies (utilizing video of classroom practice) in an attempt to establish reliability and validity of the new iPad®-based classroom observation instrument. The articulated results provide a good measure that this goal has been reached.