This report on the Santa Clara Plus Assessment and Activities Program describes the development of the Santa Clara Inventory of Developmental Tasks and evaluates the program's effectiveness. Intended as an observational tool for teachers concerned with the development of readiness, the Inventory provides a procedure for: (1) observing children's growth and development and assessing their individual needs; and (2) providing prescriptive programming for teachers and parents to use with individual children. The Observation Guide contains a developmental profile for each child allowing the teacher to record the child's progress in eight developmental areas: motor coordination, visual-motor performance, visual perception, visual memory, auditory perception, auditory memory, language development and conceptual development. The Inventory was tested by five learning-assistance teachers on first grade students who had shown learning and/or school adjustment problems, and with two other first grade groups: a control group of comparable students and a group of high-achieving readers. Findings indicated that good performance on the Inventory was not in itself sufficient to produce reading success. Factors such as language development, native intelligence and social-emotional development also appear to contribute to reading achievement. (Author/BF)