This document discusses how service level agreements (SLAs) need to evolve with the adoption of outcome-based pricing models for business process as a service (BPaaS). It notes that outcome-based pricing is still rare and that SLAs will need to be expressed in business terms and measured by business outcomes rather than technical metrics. It also introduces CAST software as a tool that can help measure SLAs in a BPaaS environment by identifying key performance indicators (KPIs) linked to business outcomes and benchmarking them over time to establish baselines and monitor performance.