The City of Boston has historically collected and published performance data through its budget process each year. In 2002, the City moved to an electronic collection system, which was upgraded in 2006 to a state-of-the-art online performance management system utilized by thousands of public and private sector organizations. Today, BAR collects data on hundreds of performance measures from a wide range of departments in a centralized system that integrates a department's mission, strategies, measures and resources.

Throughout this process of technological upgrades, the City of Boston has also sought to strengthen the quality and usefulness of the performance data collected. Each year, departments are given the opportunity to revise their performance measures and with an eye towards better capturing the work they do and improving the City's management capacity. As a result of this process of continuous improvement, the Mayor's Performance Reports may not have performance history for each measure going back to fiscal year 2006.