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	Blockad laboratorieexperiment	Blockad randomiserad kontrollerad studie (blockad RCT)
Ämnesområde	Försöksplanering	Försöksplanering
Familj	Process / pipeline	Process / pipeline
Ursprungsår	1926–1935	1920s (Fisher's blocking principle); applied to RCTs from the 1940s onward
Upphovsperson	Ronald A. Fisher	R. A. Fisher (blocking principle); systematic RCT application by Bradford Hill and later Pocock, Friedman et al.
Typ	Controlled experimental design with blocking	Experimental design
Ursprungskälla	Fisher, R. A. (1935). The Design of Experiments. Oliver and Boyd.	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
Alias	blocked lab experiment, laboratory randomized block design, RBD laboratory study, blocked within-lab experiment	blocked RCT, block-randomized trial, stratified block randomization trial, permuted block randomization
Närliggande	5	5
Sammanfattning	A blocked laboratory experiment is a controlled laboratory study in which experimental units are grouped into homogeneous blocks before treatment assignment, and treatments are then randomly assigned within each block. Blocking removes the influence of a known nuisance variable — such as participant batch, equipment run, or testing day — from the error term, increasing the precision of treatment comparisons without expanding sample size.	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.