This paper investigates the "chilling effect" of arbitration hypothesis using data from public sector collective bargaining activity in Minnesota. Settlement rates under a regime requiring the compulsory arbitration of impasses are compared to rates under a regime permitting a limited right to strike. The authors find a significantly lower settlement rate under the pure arbitration regime. Other factors that could result in this rate differential are discussed. While not ruling out the possibility of unmeasured differences, the authors conclude that the differential is due to differences in regime and not to the confounding factors discussed.