مقایسهٔ روش‌ها

	مجموعه موارد - مطالعه مشاهده‌ای توصیفی	مطالعه مورد-شاهدی تودرتو
حوزه	اپیدمیولوژی	اپیدمیولوژی
خانواده	Process / pipeline	Process / pipeline
سال پیدایش	Longstanding; systematized in 20th century clinical research	1973–1977
پدیدآور	Historical clinical practice; formalized in modern evidence-based medicine literature	Nathan Mantel (1973); D. C. Thomas (1977 formalization)
نوع	Observational descriptive study	Hybrid observational study design
منبع بنیادین	Case series. Wikipedia.	Thomas, D. C. (1977). Addendum to: Methods of cohort analysis: Appraisal by application to asbestos mining. Journal of the Royal Statistical Society, Series A, 140(4), 469–491.
نام‌های دیگر	case series report, clinical case series, consecutive case series, patient series	NCC study, nested CC design, case-control within cohort, density sampling case-control
مرتبط	5	6
خلاصه	A case series is a descriptive observational study that documents the characteristics, clinical course, and outcomes of a group of patients who share a common condition, exposure, or intervention. Unlike case reports, which focus on a single patient, a case series aggregates data across multiple patients (typically three or more) to identify patterns, generate hypotheses, and characterize rare or novel conditions — without a concurrent control group.	A nested case-control study is an efficient observational design embedded within a defined cohort. For each participant who develops the outcome of interest (a case), a small number of matched controls are sampled from those still at risk at the same point in time. This density-sampling strategy yields odds ratios that approximate incidence-rate ratios from the full cohort at a fraction of the data-collection cost — making it the preferred alternative when measuring exposures for all cohort members would be prohibitively expensive or technically demanding.