Field testing, the last step in the developmental cycle for educational products, must ascertain whether the test product, placed in a natural environment, will actually elicit the behavioral changes it was designed to effect. A systems approach to field testing requires that certain basic areas of investigation first be established. Specific field testing goals should be selected. A test site should be chosen to incorporate all factors considered mandatory to product installation. All testing costs should be determined and essential funding arrangements made. Agreements can then be negotiated with key personnel at the most promising test sites. Accurate logistic assessments are necessary for costing and scheduling purposes and for efficient test execution. After the elements of time scheduling and staff preparation (both initial and ongoing) have been dealt with, instruments must be chosen for measuring the test program's outcomes, and standards for assigning values to these measured outcomes must be set up. As data is evaluated, test reports should be issued to provide two-way communication between operators and decision makers, and to document the test for future reference. Following the final product revision, the information gained in testing should be disseminated. (JY)