Patent claims and patent scope

Patent scope is one of the important aspects in the debates over “patent quality.” The purported decrease in patent quality over the last decade or two has supposedly led to granting patents of increased breadth, decreased clarity, and questionable validity (in part due to over-breadth). Such patents allegedly diminish the incentives for innovation due to increased transaction costs in the market for technology, more frequent disputes and litigation, trolling behavior, and breakdowns in bargaining. This paper focuses on the patent examination process at the PTO, highlighting the relationship between patent scope and the patent examination process. We develop and validate two measurements of patent scope: independent claim length and independent claim count. These metrics—in contrast to other measurements of patent scope—can be calculated before and after examination and enable us to provide the first large-scale analysis of trends in patent scope changes during the examination process. Our results show that applications with narrower scope are associated with a higher probability of grant and a shorter and less intense examination period in comparison to applications with broader scope. Further, we find that the examination process itself tends to narrow the scope of patents relative to the scope at filing, and that the changes are more significant when the duration and intensity of examination is increased. We explain our metrics and make our data available in a public use dataset, which we hope will encourage more research in the evaluation of patent scope, patent examination, and patent quality more broadly.