The development and validation of an instrument designed to measure the quantity of types of instruction delevered to individual students is described. The Classroom Activities Log (CAL) is a teacher-completed record of students' instructional experiences, and may be used to study educational equity questions posed by Elementary Secondary Education Act Title I mandates. Some of the features of CAL are: (1) student focus; (2) limited number of variables; (3) minimal teacher training and costs; (4) availability of data on individual students' daily activities; and (5) ease of scaling. The school day is divided into ten-minute periods, and thirteen content areas are quantified: language arts; English as a second language; mathematics; social studies; science; fine and applied arts, home economics, shop, or foreign languages; physical education, health and safety; career education; cultural enrichment; special services; recess, lunch or unoccupied; classroom management; and other. Information is also provided on size of the instructional group, type of adult involved in the instruction; bilingual instruction; and compensatory education programs. It is concluded that reliability estimates (based on correlations between teacher and observer ratings) are acceptable, and that there is a certain degree of construct validity. (MH)