The document discusses measuring project performance through key performance indicators (KPIs). It states that while tracking time, cost and scope seems straightforward, measuring performance is more complex. It is important to determine what exactly is being measured, such as a single project's success, overall project performance, or project management effectiveness. Common KPIs include schedule adherence, budget compliance, issues, changes, defects, and stakeholder satisfaction. Performance reports summarize work performance data and information to update stakeholders on project status and forecasts.