How long should the observation period be? Can it be done over the course of several days?

The scales were designed to be used during an observation period of at least 2½ hours, but generally the assessor stays for at least 3 hours in the classroom give or take a few minutes. Depending on when the children arrive and when they go down for a nap, this can vary somewhat. The assessor will complete his/her observation first, then he/she interviews the caregiver for about 30 minutes to answer some questions. It would be possible to do the observation in shorter periods over the course of several days; however; the scores may not be reliable. In many ways the scales are time samples - to see whether things happen frequently enough for them to make a developmental difference to children. That is why for some items there are places where it specifies that the requirement must be observed at least once, or perhaps more, during the observation. If a teacher is given three different opportunities on three different days to show that behavior, it may be given credit, while if the observation had been done in only one morning, it might not.