The proposition that men and women perpetrate partner violence equally would make partner violence unique with respect to other forms of interpersonal violence. Women, however, commit a substantial minority of violent acts. Any theory of gender patterns in partner violence needs to be reconciled with other violence data. Data on other violence indicate that different methodologies sample from different sets of phenomena, and those methods that sample the least severe violence show greater gender equivalence. Interpretation is clouded, however, by underreporting and overreporting across methodologies. Despite improvements in self-report measures, partner violence measurement lacks a gold standard. A gold standard would include incident data, sexual violence, injury, and be developed through direct comparison of multiple methods, including perhaps real-time self-monitoring.