The success of any video study hinges on the quality, informativeness, and comparability of the tapes collected. What we see on a videotape results not only from what transpires in the classroom, but also from the way the camera is used. Therefore we constructed standardized procedures for camera use, and trained videographers in the application of these procedures. Only one camera was used to videotape each lesson, and it usually focused on the teacher.

A field test was conducted with nine classrooms in each country prior to commencement of data collection. These field test tapes were used, in part, as a basis for developing codes.