The development and consistent use of reliable and valid PROs and performance-based measures of physical functioning may expedite development of improved pain treatments, and standardization of these measures has the potential to facilitate comparison across studies. We provide recommendations to stimulate future methodological research to develop tools that are more robust, address consistency and standardization, and engage patients early in the tool development process. Assessment of Function4

Improved reporting standards, and adoption of experimental protocols that emphasize control of experimental bias, are likely to improve understanding and confidence in pain biology.