قارن الطرق

	Multicenter Case-Crossover Design	دراسة الحالة والشاهد المتداخلة (Nested Case-Control Study)
المجال	علم الأوبئة	علم الأوبئة
العائلة	Process / pipeline	Process / pipeline
سنة النشأة	1991 (core design); multicenter extensions 1990s–2000s	1973–1977
صاحب الطريقة	Malcolm Maclure (single-center design, 1991); multicenter applications developed through 1990s–2000s environmental and pharmacoepidemiology literature	Nathan Mantel (1973); D. C. Thomas (1977 formalization)
النوع	Observational epidemiological design	Hybrid observational study design
المصدر التأسيسي	Maclure, M. (1991). The case-crossover design: A method for studying transient effects on the risk of acute events. American Journal of Epidemiology, 133(2), 144–153.	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.
الأسماء البديلة	multi-site case-crossover study, multicenter self-matched crossover, multi-center transient exposure study, MCCO study	NCC study, nested CC design, case-control within cohort, density sampling case-control
ذات صلة	4	6
الملخص	The multicenter case-crossover design is an observational epidemiological method that investigates whether brief, transient exposures trigger acute health events by comparing each case's exposure just before the event to their own exposure during matched control periods — with data collected from two or more independent clinical or geographic sites to increase power, external validity, and the ability to detect site-level effect modification.	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.