手法を比較

	後向き第II相臨床試験	後ろ向きコホート研究
分野	疫学	疫学
系統	Process / pipeline	Process / pipeline
提唱年	1980s–1990s (with growth in oncology retrospective analyses)	Mid-20th century (widely formalized 1950s–1970s)
提唱者	Adapted from standard Phase II trial methodology; retrospective variant formalized in oncology practice	Systematic use attributed to early 20th-century occupational epidemiology; formalized in modern epidemiological theory by Brian MacMahon and others
種類	Observational retrospective study	Observational analytic study
原典	Simon, R. (1989). Optimal two-stage designs for phase II clinical trials. Controlled Clinical Trials, 10(1), 1–10.	Rothman, K. J., Greenland, S., & Lash, T. L. (2008). Modern Epidemiology (3rd ed.). Lippincott Williams & Wilkins. ISBN: 978-0781755641
別名	retrospective Phase II study, historical Phase II analysis, retrospective efficacy study, Phase II retrospective analysis	historical cohort study, non-concurrent cohort study, retrospective follow-up study, historical prospective study
関連	5	6
概要	A retrospective Phase II clinical trial evaluates a treatment's preliminary efficacy and safety signals using existing archival data — medical records, registries, or electronic health records — rather than prospectively enrolling new patients. It mirrors the objectives of a standard Phase II trial (estimating response rate, tolerability, and early efficacy) but does so by looking backward at patients who have already received the intervention, making it faster and less costly than a prospective design.	A retrospective cohort study assembles a group of individuals who share a common starting point and reconstructs their exposure history and subsequent outcomes entirely from pre-existing records. Because the data have already been collected before the study begins, the design is far faster and cheaper than a prospective cohort; however, the researcher must work with whatever information was recorded at the time rather than collecting purpose-built measurements.