Practical experiences in developing and introducing performance measurements systems for measuring and managing knowledge capital have shown that these instruments do not sufficiently fulfil the expectations of their users. Some authors even point out that the fundamental understanding of methodological and conceptual issues is inade‑quate. Therefore, we suggest that instead of creating further new instruments, an explanation of how and when Perform‑ance Measurement Systems (PMS) become effective is necessary. We argue that highlighting their potential production of "blind spots" and comprehending the use of PMS more reflexively will bring more sustainable effects. As a result, the concept of First and Second Order Reflection of PMS is introduced.