The article discusses challenges in accurately measuring patent indicators due to changes in the patent system and access to patent data. It focuses on international patent application flows between the US, Europe, and Southeast Asia, and how to compare them effectively. The use of the Patent Cooperation Treaty (PCT) route and the Cooperative Patent Classification (CPC) system are highlighted as important for search strategies and result interpretation. The chapter also delves into the patenting activities of large companies and the value of patents.