Pharmaceutical claims may be generally categorized into four groups: compound, composition (which includes formulation), method of treatment, and process of preparing. This chart evaluates rates of unpatentability/cancellation for each group relative to claims originally challenged in petitions. While still a small sample size (particularly for compound and process-of-preparing claims), the relative success rates reflect conventional wisdom – compound claims fare best, with composition claims not far behind and method of treatment claims trailing more significantly. These statistics do not account for redundancies (which were deemed immaterial). The claims were categorized based on the class as claimed, rather than attempting to determine a likely key feature recited (e.g., whether a particular composition was recited in a claimed method of treatment).