The report discusses the development of written job proficiency examinations for four Mail Processing Equipment (MPE) positions (MPE apprentice, MPE mechanic, MPE senior mechanic, and MPE supervisor). After a brief introductory chapter, the next chapter describes the determination of examination objectives and the desirability of testing specific job knowledge and the aptitude for acquiring future job qualification knowledges, but not job skill, personality factors, and physical characteristics. Chapter 3 discusses the preparation of the examination items (of the five-alternative multiple choice variety) based on an analysis of maintenance and supervisory skills, the purpose of which was to test minimum knowledge standards while at the same time assuring an adequate supply of successful applicants. Chapter 4 discusses the preliminary administration of the 384 items to a sample of maintenance personnel currently engaged in job activities that correspond to the proposed job descriptions at the 13 most highly mechanized post offices. Chapter 5 covers the selection of 339 test items, the assignment of the items to the four qualifying examinations, and the minimum standards for determining job qualification. Chapter 6 discusses test validity and makes suggestions to the Post Office Department for broadening the assessment of worker qualifications. (JR)