This study compares the structure of E, V frontiers under several specifications of expected income and variance parameters with emphasis on fundamental differences in efficient crop mixes. The results are generated using data from a specific production region and a selected set of cropping activities for Wyoming. The risk-efficient frontiers and underlying crop mixes display sensitivity to alternative parameter definitions and suggest that if researchers intend to use the E, V approach in providing decision information to producers, care should be exercised in the choice of income and risk measures.