Discusses an investigation of relationships between academic achievement in science, as measured by the National Assessment of Educational Progress science exercises, and self-concept as measured by the Self Appraisal Inventory, using Iowa public school pupils in grades four, seven, and twelve but excluding pupils enrolled in special education classes. Pupils were randomly selected using a multistage cluster sampling technique. (PEB) Aspect of National Assessment (NAEP) dealt with in this document: Procedures (Replication).