This module, the first of four units about vocational competency measurement, is module 17 in the Vocational Education Curriculum Specialist series. The purpose stated for the document is to trace the growth of the formal measurement of skills, knowledge, and attitudes in vocational programs and to present some uses of competency testing in vocational programs. Content is organized into three sections, each of which focuses on one goal and two or more objectives. Section 1 examines the growth and significance of student competency testing in vocational education programs. In the second section, the components that make up a comprehensive set of vocational competency measures are described. The discussion also covers definitions used for various testing techniques. The module concludes with an overview of the uses of competency measures for evaluation, instruction and administration, and communication among instructors, administrators, students, and parents. Each section concludes with individual study activities, discussion questions, and group activities. Self-check items and possible responses to them are appended for use as a pretest and review of the module content. (YLB)