قارن الطرق

	Cluster Randomized Controlled Trial	النمذجة متعددة المستويات
المجال	التصميم التجريبي	إحصاء البحث
العائلة	Process / pipeline	Process / pipeline
سنة النشأة	1978–1980s	1992
صاحب الطريقة	Cornfield (1978); systematised by Donner and colleagues (1980s)	Anthony Bryk and Stephen Raudenbush
النوع	Experimental design	Method
المصدر التأسيسي	Donner, A., & Klar, N. (2000). Design and Analysis of Cluster Randomization Trials in Health Research. Arnold. ISBN: 978-0340652978	Bryk, A. S., & Raudenbush, S. W. (1992). Hierarchical Linear Models: Applications and Data Analysis Methods. SAGE Publications.
الأسماء البديلة	cluster RCT, group-randomized trial, community randomized trial, cluster-randomized experiment	HLM, mixed-effects models, random effects models, MLM
ذات صلة	4	3
الملخص	A cluster randomized controlled trial (cluster RCT) is an experimental design in which intact social or organisational groups — such as schools, clinics, villages, or workplaces — are randomly assigned to treatment conditions rather than individual participants. Outcomes are still measured at the individual level, but the unit of randomization is the cluster. This design is essential when an intervention is delivered to whole groups, when there is a risk of contamination between participants in the same setting, or when individual randomization is logistically or ethically impractical.	Multilevel modeling (also called hierarchical linear modeling, mixed-effects modeling) is a statistical framework for analyzing data organized in nested or clustered structures—students within schools, patients within hospitals, repeated measures within individuals. Developed by Bryk and Raudenbush (1992), it accounts for dependency among observations and partitions variance into levels (within-cluster and between-cluster), enabling valid inference and revealing context effects. Essential in education, medicine, organizational research, and any field where data have natural hierarchies.