So sánh phương pháp

	Thiết kế nghiên cứu cắt ngang	Thiết kế nghiên cứu trường hợp-chứng
Lĩnh vực	Nghiên cứu lâm sàng	Nghiên cứu lâm sàng
Họ	Process / pipeline	Process / pipeline
Năm ra đời	1950s-1970s	1950s-1970s
Người khởi xướng	Epidemiologists in the mid-20th century; formalized by Kelsey, Rothman, and others	Jerome L. Schlesselman, Brian MacMahon, Thomas Pugh
Loại	Research Design	Research Design
Công trình gốc	Kelsey, J. L., Whittemore, A. S., Evans, A. S., & Thompson, W. D. (1996). Methods in Observational Epidemiology (2nd ed.). Oxford University Press. ISBN: 978-0195083299	Schlesselman, J. J. (1982). Case-Control Studies: Design, Conduct, Analysis. Oxford University Press. ISBN: 978-0195027815
Tên gọi khác	prevalence study, cross-sectional survey, snapshot study, survey design	case-control study, retrospective study, matched case-control, nested case-control
Liên quan	2	2
Tóm tắt	A cross-sectional study (or prevalence study) measures exposure and outcome simultaneously at a single point in time, producing a 'snapshot' of a population. Respondents are recruited and surveyed (or examined) on the same occasion, capturing current prevalence of both exposure and disease. Cross-sectional studies are simple, quick, and inexpensive, making them popular for needs assessments, surveillance, and generating hypotheses—though they cannot establish causality due to lack of temporal sequence.	A case-control study identifies individuals with a disease or outcome (cases) and a comparison group without the outcome (controls), then measures prior exposure retrospectively. Developed in the 1950s–1970s by epidemiologists like Schlesselman and MacMahon, case-control studies are especially efficient for rare diseases, as they sample cases enriched for the outcome, avoiding the need for enormous cohorts. They are a mainstay of clinical epidemiology, observational research, and outbreak investigations.