This document discusses effective contract metrics for delivering business value. It argues that traditional software development contracts focus too much on output-based requirements and activity-based sequential development metrics, which increase failure risks and lower returns on investment. An "Evolve" contract is proposed that uses results-focused modular structures, allows for changes and learning, and employs various metrics like output targets or throughput targets suited for complex and unpredictable software development. This new contract model is needed to better manage complex contexts and environments through experimental and feedback-driven approaches.