The Certification Authorities Software Team (CAST) issue guidance on various issues regarding the interpretation of DO-178B and DO-178C. In the CAST 10 paper, they discuss the interpretation of a “decision”. Three possible interpretations are made. The first is a “literal” interpretation of DO-178B, namely a Boolean expression composed of conditions and zero or more Boolean operators.The second is a “relaxed” interpretation of DO-178B, namely a decision is equivalent to a branch. The third is an intermediate position, where the literal interpretation applies to MC/DC, and the relaxed interpretation applies to branch coverage. Our coverage tool, RapiCover, supports both interpretations to provide maximum flexibility.