In their constant groping toward achievement standards, the high schools of this country have developed what is known as "cooperative testing." This development is not recent. Cooperative testing dates back further than the standardized testing movement itself. For instance, it has been customary for about 50 years in New York and in certain Western States to conduct State high-school examinations. This type of testing was developed through the desire to standardize and supervise high-school instruction. There also developed at an early date a form of testing designed as a means of determining admission to college. In the last decade, particularly in the last 5 years, cooperative testing has been stimulated through the measurement movement. There is a reason for the increasing popularity of cooperative testing. It is in advance over the use of tests by individual schools or school systems because in cooperative testing a group of schools, usually in a fairly well-defined geographical area, agree to give the same test under uniform conditions to their students so that the work of the individual students in one school can be compared with the work of the students in all schools. This intimate comparison tends to bring about a better understanding of the achievement and ability of the pupils in a given area. Whereas national norms classify the work of pupils in a general way they have not always been found to fit the achievement of pupils in these various geographical areas as well as results of tests given cooperatively. This is more true for the high-school level than for that of the elementary school because of the differing courses of study in each high-school subject in the different geographical areas. This bulletin is restricted to cooperative testing programs in the United States which are State and national in character. We are not restricting it to programs carried forward by State departments, but include all programs which cover large portions of the nation or a State, regardless of the agency which is sponsoring it. Only programs relating to grades 9 to 12, inclusive, are considered. A cooperative testing program is defined as one initiated and carried through for the mutual benefit of all concerned and without a commercial aspect. An appendix provides the name of the person, if known, in charge of each testing program, and the references describing the programs. (Contains 6 footnotes.) [Best copy available has been provided.]