This paper contains optional modifications and additions to the Brophy-Good Dyadic Interaction Coding Manual (ED 042 688). Included are 1) suggestions for changes in the way level-of-question is coded; 2) modifications of the child's answer categories for simplification or expansion; 3) new distinctions for coding the teacher's feedback following correct responses from the children (allowing expansion and diversification of the four categories). Also described are new categories for use at the secondary level which have been added to cover affective aspects of teacher-pupil interaction and increased student activity (student initiated response opportunities, joking, and personal conversation). The two basic types of measures which can be derived from the system are discussed: simple frequency counts (quantitative) and percentage scores (qualitative). Twenty-six of the more useful frequency measures are listed, and 50 percentage measures of teacher-child interaction are listed under the various categories: measures of teacher vs. child initiation of dyadic interactions; student initiated response opportunities over total response opportunities; level-of-question measures; types of dyadic interaction; child performance measures; praise and criticism of academic performance; praise and criticism of behavior; quality of feedback; and sustaining the interaction after the initial response opportunity. (JS)