• mammography screening;
  • quality improvement;
  • trend analysis

Abstract: This retrospective cohort study determined trends and patterns of mammography rates during 5 years (1997–2001) among female Medicare beneficiaries ages 50 years and older in Connecticut to better understand changes in rates over time and to plan future interventions. Time series analysis and hierarchical longitudinal logistic regression were used to assess changes over time. Mammography rates increased significantly during the 5-year period (p < .001). A cyclical pattern was observed for all age groups and counties, with dips and peaks in the spring and fall each year (average increase 8% per year), consistent with concentrated intervention activity at those times.