So sánh phương pháp

	Chuỗi ca bệnh	Nghiên cứu bệnh-chứng lồng ghép
Lĩnh vực	Dịch tễ học	Dịch tễ học
Họ	Process / pipeline	Process / pipeline
Năm ra đời	Longstanding; systematized in 20th century clinical research	1973–1977
Người khởi xướng	Historical clinical practice; formalized in modern evidence-based medicine literature	Nathan Mantel (1973); D. C. Thomas (1977 formalization)
Loại	Observational descriptive study	Hybrid observational study design
Công trình gốc	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.
Tên gọi khác	case series report, clinical case series, consecutive case series, patient series	NCC study, nested CC design, case-control within cohort, density sampling case-control
Liên quan	5	6
Tóm tắt	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.