This application's goal is the creation of a Cervical Cancer Data & Research Unit, within an existing PROSPR Center, that can completely evaluate the cervical cancer screening process and actively engage in PROSPR collaborative projects. Cervical cancer is largely preventable with appropriate screening, yet the implementation of new techniques, such as human papilloma virus (HPV) testing, has created important challenges regarding how to: optimize new screening methods, minimize screening failures by understanding how and why they occur; and diminish overscreening (since, for >99% of women, screening results in only worry and risk). The proposed Unit, within an existing productive PROSPR collaboration of Kaiser Permanente Northern California and Southern California, can address these critical questions using three strengths. 1) A very large community-based cohort with, for the years 2010-2013 alone: >4.8 million screening eligible women; marked demographic diversity (>1,330,000 Hispanic, 589,000 Asian, and 390,000 African American members); detailed screening data (>2.7 million Pap smears, 2.1 million HPV tests, and 600,000 HPV vaccinations); large numbers of rare outcomes (>800 invasive cancers); socioeconomic diversity (including >54,000 with safety-net payors such as Medicaid); health plan and provider diversity (>35 medical centers, >4000 primary care/OB-GYN physicians throughout California); and a full spectrum of high-quality individual cancer risk data within readily accessible electronic laboratory, pharmacy and pathology data sources extending to before 2005. 2) A successful existing PROSPR colorectal cancer center that has been productive within and across the PROSPR network, delivered this year 192 different screening data elements on almost 2.6 million screening-eligible patients, co-led the development of new data elements across PROSPR centers for exam indications and comorbidities and already published high impact PROSPR manuscripts. 3) An expert team in cervical cancer screening, led by two co-Principal Investigators funded in cervical cancer screening research, complemented by a transdisciplinary group of researchers and expert consultants in obstetrics/gynecology, cancer and infectious disease epidemiology, oncology, pathology, modeling, cohort biostatistics, screening quality, and health care delivery. Together, the new Unit can efficiently evaluate the full cervical cancer screening and follow-up - process, put screening actions within the context of comprehensive health care data, and lead PROSPR collaborative studies, such as those described in the Research Plan, that can evaluate the comparative effectiveness of different screening strategies, identify causes of screening failures, and examine the impact of HPV vaccination on screening uptake and outcomes.