This chapter explores factors that affect reliance on combat identification (CID) systems, with the end goal of helping soldiers to use the systems more effectively and reduce fratricide incidents. A variety of technical solutions have been developed to improve soldiers CID performance. The chapter examines the effectiveness of using aid reliability information to support appropriate reliance on a simulated, rifle mounted, and CID system. It describes test the feasibility of using response bias as an indication of participants' reliance on the CID aid. In the systems, soldier is equipped with a gun-mounted interrogator and a helmet-mounted transponder. The chapter examines whether informing participants about the reliability of the aid affected participants' reliance on the aid. A participant's decision to rely on the aid more often than ignoring it may be appropriate, especially in the case where the aid outperforms manual control.