Economic regulators play an important role in sectors that deliver essential services to citizens and the economy. Robust performance assessment helps regulators understand where to adjust their approach to improve outcomes. According to the OECD Best Practice Principles on the Governance of Regulators, a well-designed performance framework serves multiple goals: demonstrating the effectiveness of the regulator, building confidence in the regulatory system and driving improvements (OECD, 2014). Performance assessment is a critical ingredient for maintaining accountability and fostering transparency, and public bodies are often required to report on results and enable scrutiny of their performance. Data on the performance of both the regulator and the regulated sector are an important ingredient of economic regulators’ performance assessment frameworks. The results can also be part of organisational learning, providing inputs into decision making.