Building process improvement capacity in epidemiologic research operations: The Nurses' Health Study experience

With declining infrastructure funding for large-scale epidemiologic cohort studies, continuous process improvement is essential to sustain research quality and impact. The authors recently undertook a Lean Six Sigma (LSS) training initiative with operational staff of the Nurses Health Studies, among the longest-running and most productive cohort studies, to modernize operations and build internal capacity for process improvement. Twenty staff members across operational domains completed a structured LSS curriculum and three improvement projects: (1) reducing median turnaround time for medical record retrieval by 90%, (2) decreasing the proportion undeliverable questionnaires by 31%, and (3) cutting biweekly freezer maintenance time by 43 person-minutes per cycle, yielding an estimated 6.5 person-weeks annually. Staff reported substantial increases in understanding and confidence in applying process improvement methods. Fourteen trainees completed all requirements for LSS green-belt certification. Though some participants questioned the need to learn a specialized framework, most valued the collaborative, data-driven approach. This experience demonstrates that LSS can be successfully adapted to non-clinical trial epidemiologic research, improving efficiency and data quality. The results support broader adoption of structured continuous improvement efforts to enhance the sustainability of epidemiologic research platforms.