Linganisha mbinu

	Utafiti wa Kesi-Udhibiti Retrospective	Utafiti wa Cohort
Nyanja	Epidemiolojia	Epidemiolojia
Familia	Process / pipeline	Process / pipeline
Mwaka wa asili	1950s–1960s (formal methodology)	Mid-20th century (formal epidemiological design codified ~1950s)
Mwanzilishi	Jerome Cornfield; formalized by Brian MacMahon and others in mid-20th-century epidemiology	Doll & Hill (British Doctors Study, 1951); Snow (cholera, 1854)
Aina	Observational analytical study	Observational longitudinal study design
Chanzo asilia	Schlesselman, J. J. (1982). Case-Control Studies: Design, Conduct, Analysis. Oxford University Press. ISBN: 978-0195029338	Rothman, K. J., Greenland, S., & Lash, T. L. (2008). Modern Epidemiology (3rd ed.). Lippincott Williams & Wilkins. ISBN: 978-0781755641
Majina mbadala	case-control study, retrospective case-referent study, case-referent design, trohoc study	longitudinal study, follow-up study, panel study, incidence study
Zinazohusiana	5	6
Muhtasari	A retrospective case-control study identifies individuals who already have an outcome of interest (cases) and a comparable group without it (controls), then looks backward in time using existing records to determine prior exposure to a suspected risk factor. The primary measure of association is the odds ratio. This design is especially efficient for studying rare diseases or outcomes with long latency periods, since the outcome has already occurred before the study begins.	A cohort study assembles a group of individuals who share a common starting point — typically freedom from the outcome of interest — and follows them over time to observe who develops the outcome. By comparing incidence rates between exposed and unexposed subgroups, researchers can estimate relative risk and absolute risk differences. Cohort studies are the gold-standard observational design for measuring disease incidence and establishing temporal relationships between exposure and outcome.