The emergence and purpose of formative evaluation as a tool for curriculum developers is described. It is pointed out that formative evaluation seeks to establish the merit of instructional materials during their development, to modify and improve the design of instructional materials, and to establish their worth so they may be adapted for use in local contexts. The value of formative evaluation in the development of global education materials is explored. A discussion is presented on formative evaluation methods and procedures, including: (1) pilot testing materials in the field; (2) use of prototype materials during pilot testing; (3) use of entire sets of materials during pilot testing; (4) determining the size and scope of pilot tests; (5) purpose and procedures of site visits during pilot testing; (6) composition and contributions of panels of experts; and (7) purposes and advantages of teacher and student evaluations and questionnaires. A description is presented of the use of formative evaluation in developing a curriculum for a Global Studies in Geography Project for middle school social sciences students. Problems faced by developers in adapting materials to the abilities and interests of both students and teachers are discussed. Recommendations and guidelines are offered for planning and expediting a formative evaluation. (JD)