This publication is one in a series of 12 giving the recommendations that were made for a broad and balanced education program in science for young people. This guide aims to raise key issues about assessment; provides a measure of up-dating with regard to development; encourages science teachers and departments to reflect on their current practice; and is based on the belief that there is a need to change the emphasis towards formative, criterion-referenced assessment with greater involvement of the young person. Section one deals with overview groups, overt and implied assessment groups, and the total package groups. Section two considers GCSE, grade related criteria, achievement, graded assessment, accreditation, and assessment of practical work. Section three presents learning about assessment and section four gives recommendations. An introduction, a glossary, additional readings, references, appendices on graded assessment in science schemes, and pre-vocational and other developments are also provided. (RT)