Observer reliability and the confusability of codes, two sources of error in the collection of classroom observational data, are examined. Confusability is defined as the extent to which one code is mistakenly recorded as another code. Observational data were collected in each of 172 first grade and 171 third grade Follow Through and comparison…

Presented as a mini-course on the design of classroom observation systems, this report stresses the necessity of determining the goals of any study before designing the procedures. Only if the researcher has concretely formulated the questions to be answered, can an observation system be developed that will provide the appropriate data. The…