In recent years much attention has been given to criterion-referenced measures which relate test performance to absolute standards rather than to the performance of others. Popham and Husek (1969) provide a readable account of the differences between such measures and the more traditional norm-referenced tests. The purpose of this paper is to synthesize some of the literature on establishing standards and determining the number of items needed in criterionreferenced measures.This paper is written from the following perspective. A domain (i.e., population) of dichotomously scorable test "items" is conceptualized. This population of items need not actually exist. What is important, though, is that it is described well enough so that a relatively high degree of agreement can be reached about which kinds of items are or are not members of the population. In practice, only a reasonably representative sample of items is required. 2 Theoretically, the items of a domain may be relatively heterogeneous in content, form, and difficulty. In practice, however, they should be measures of a limited number of skills and knowledges so This investigation was supported in part by the Instructional Objectives Exchange while the author was on leave from Cornell University. The reactions of Wells Hively, Paul Cieslak, and two referees to an earlier draft of this paper are gratefully acknowledged.2 In contrast to criterion, the term domain is reserved for the case where an item generation procedure is employed or a universe is postulated and the items used are considered to be a representative sample. Cronbach and his colleagues (1963, 1972) used the notion of a universe of test items in a theory of reliability. Osburn (1968) seems to have made the first in-print statement of the precise * definition of domain. One set of procedures for generating such a domain makes use of item forms. A thorough description of the techniques and examples may be found in Maxwell, Hively, Lundin, Rabehl, & Sension (1971) with further descriptions and extensions in Mussell (1969) and Rabehl (1971). Other item generating schemes have been proposed by Anderson (1972), Bormuth (1970), Guttman (see, e.g., Jordan, 1971), and to some extent by Scandura (see, e.g., Durnin & Scandura, 1971).A less formal way of conceptualizing a domain of items is to construct first an "amplified objective" (Popham, 1972) in which elements from content and method facets included in and excluded from the domain are identified. This procedure is being followed in the development of objectives-based tests in the basic skill areas published by the Instructional Objectives Exchange,