This volume is one of the products of the knowledge development effort implemented under the mandate of the Youth Employment and Demonstration Projects Act of 1977. It is a report of an assessment study designed to determine the status and results of the implementation of mixed income experiments at 47 Comprehensive Employment and Training Act (CETA) sites during fiscal years 1978 and 1979. Mixed income experiments are designed to test whether and/or to what extent income-eligible youth benefit from working with and being trained alongside nonincome-eligible youth, as opposed to receiving the same services in projects where all participants are income eligible. Data were collected from program plans and project reports, telephone inquiries to prime sponsors, and site visits. The conduct of these mixed income experiments and their individual findings vary significantly, making any aggregate analysis difficult. Each of the tests in varying degrees failed to meet accepted practices in research methodology, and therefore the results of this knowledge effort are inconclusive. From what operational data were gathered, however, no conclusive evidence of benefit to youth participants was shown, and no change in low-income guidelines for participants is warranted. The mixed income hypothesis, however, does warrant further investigation. It is recommended that future experimental efforts follow stricter research guidelines. (The report includes a brief case study of the tests conducted.) (Other youth knowledge development reports are available through ERIC--see note.) (KC)