השוואת שיטות

	מבנה ניסויי אקראי מבוקר-קבוצות-אשכול	ניסוי מבוקר אקראי חסום
תחום	תכנון ניסויים	תכנון ניסויים
משפחה	Process / pipeline	Process / pipeline
שנת המקור	1990s (formal methodology development)	1920s (Fisher's blocking principle); applied to RCTs from the 1940s onward
הוגה השיטה	Murray, D. M.; Donner, A. and Klar, N. (systematic formalization)	R. A. Fisher (blocking principle); systematic RCT application by Bradford Hill and later Pocock, Friedman et al.
סוג	Experimental design	Experimental design
מקור מכונן	Donner, A., & Klar, N. (2000). Design and Analysis of Cluster Randomization Trials in Health Research. Arnold. ISBN: 978-0340691533	Friedman, L. M., Furberg, C. D., DeMets, D. L., Reboussin, D. M., & Granger, C. B. (2010). Fundamentals of Clinical Trials (4th ed.). Springer. ISBN: 978-1441915856
כינויים	CRCT with control group, group-randomized trial, cluster RCT control group design, community randomized controlled trial	blocked RCT, block-randomized trial, stratified block randomization trial, permuted block randomization
קשורות	6	5
תקציר	A cluster randomized control group experimental design randomly assigns intact groups (clusters) — such as schools, clinics, or communities — rather than individuals to treatment or control conditions. At least one cluster group receives no active intervention, serving as the control. This design is essential when individual randomization is impractical or contamination between participants in close proximity is likely.	A blocked randomized controlled trial (blocked RCT) uses permuted-block randomization to ensure that treatment groups remain balanced in size — and optionally in key characteristics — throughout recruitment. Within each block of fixed or randomly varied size, all treatment allocations are present in equal numbers, so imbalance cannot accumulate even if the trial is stopped early. This makes blocked RCTs the standard randomization approach in clinical and behavioral intervention research.