Compara mètodes

	Disseny experimental de pretest-posttest bloquejat	Assaig controlat aleatori amb blocs (blocked RCT)
Camp	Disseny experimental	Disseny experimental
Família	Process / pipeline	Process / pipeline
Any d'origen	1935 (blocking, Fisher); 1963 (pretest-posttest + blocking synthesis, Campbell & Stanley)	1920s (Fisher's blocking principle); applied to RCTs from the 1940s onward
Autor original	Donald T. Campbell & Julian C. Stanley (systematized); blocking technique from Ronald A. Fisher	R. A. Fisher (blocking principle); systematic RCT application by Bradford Hill and later Pocock, Friedman et al.
Tipus	Experimental design	Experimental design
Font seminal	Campbell, D. T., & Stanley, J. C. (1963). Experimental and Quasi-Experimental Designs for Research. Rand McNally.	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
Àlies	blocked pre-post design, RBPP design, block-randomized pretest-posttest design, randomized block pre-post control group design	blocked RCT, block-randomized trial, stratified block randomization trial, permuted block randomization
Relacionats	6	5
Resum	The blocked pretest-posttest experimental design combines blocking — grouping participants into homogeneous strata before randomization — with pre- and post-intervention measurement. Blocking controls for known sources of variability (e.g., baseline ability, gender, site), while the pretest-posttest structure quantifies change scores directly. Together, they reduce error variance and increase statistical power compared to a simple pretest-posttest design, making this approach well suited to educational, clinical, and behavioral intervention studies.	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.