How societies respond after women disclose sexual misconduct shapes survivors' well-being, reporting behavior, institutional accountability, and social norms. Yet, no validated measure of society's collective public response following disclosure exists. This paper introduces the Societal Response Index (SRI), a pre-registered, multidimensional framework with 5 complementary dimensions — volume & persistence (VP), secondary victimization, identity exposure, supportive/contested response, and temporal reactivation — and develops and validates its first dimension, VP. Using census-level tweet counts from the X full-archive API, I construct weekly attention series for 14 sexual misconduct cases spanning Spain, the US, and France (2011--2026). VP's three highest-attention weeks fall within two weeks of a pre-registered milestone for all 14 cases; same-day detection reaches 75% and within-14-day detection reaches 91%. VP correlates positively and significantly with Google Trends for all cases. The measurement architecture, keyword dictionaries, and event timelines will be released as a public good upon publication. As an illustration of substantive reach, official reporting of sexual offenses tends to rise following case milestones.