Emerson's exchange theory builds from the micro-social toward the macro-social level of conception, observation, and analysis. Yet although this theory is important, some of its main concepts were formulated originally in simple, categorical terms and require refinement. Some progress toward such refinement is evident in recent research on the measurement of positional power. Aiming toward further progress, the present paper proposes a procedure for measuring power imbalance at the exchange network level, reports exploratory experimental data testing the measure in a hypothesis implied by Emerson's theory, and suggests a direction for future research using the measure. [ABSTRACT FROM AUTHOR]