An important but usually neglected aspect of the training of teachers is instruction in the art of writing good classroom tests. Such training should emphasize various forms of objective items (e.g., multiple- choice, master list, matching, greater-less-same, best- worst answer, and matrix format). The proper formu lation and accurate grading of essay items should be included, as should the use of various types of free- answer items (e.g., the brief answer, interlinear, and "fill in the blanks in the following paragraph" forms). For courses involving laboratory work, such as sci ence, machine shop, and home economics, perfor mance and identification tests based on the laboratory work should be used. A second point is that organizations developing ap titude tests for nonacademic areas, such as police work, fire fighting, and licensing tests, should empha size the use by the client of a valid, reliable, and un biased criterion. Organizations developing academic aptitude tests should also (1) be alert to the accuracy of criterion measures, grades, rank in class, and so forth; (2) call teachers' attention to defects in grading; and (3) help guide teachers and schools in improving these procedures. In recent decades, there have been few instances in which a testing organization has ap prised teachers of the fact that their criteria—among others, grades on tests and student papers—are often quite unreliable based on characteristics such as work habits and attitude in class, and could be improved by using better tests to evaluate student performance. Characteristics of the group used for determining va lidity are also critical.