This manual is intended to assist teachers and supervisors by providing a set of guidelines on the design and use of methods for assessment of students' and health workers' performance. It is divided into two parts. Part 1 outlines a general approach to performance assessment, establishes a set of principles essential to the effective assessment of individual performance, and discusses current instruments or techniques that can be applied in assessment. In addition, it describes a sequential set of steps in preparing a performance assessment and follows this up with illustrations of two performance assessment procedures, concerned respectively with history-taking and blood pressure measurement. Part 2 provides some examples of instruments--mostly in the form of check-lists and rating scales--currently in use in several countries for the assessment of students' and health workers' performance. These are classified into three categories of functions or tasks: clinical proficiency, multiple tasks (comprehensive assessment), and specific tasks. Each instrument is preceded by a brief explanatory note containing this information: type of instrument, health care activity involved, category of health personnel, competences assessed, specific abilities assessed, purpose of assessment, comments, and source of further information. (YLB)