A blocked design is an experimental design where subjects or items are first grouped into blocks based on certain characteristics, and then within each block, they are randomly assigned to different treatment groups. This helps control for potential sources of variability by ensuring that each block contains similar individuals.
Related terms
Blocking Variable: The characteristic on which the blocking is done; it should be relevant to the study but unrelated to the treatments.
Within-block Comparison: Comparing individuals or items within each block separately.
Between-block Comparison: Comparing results across different blocks after accounting for variability within each block.