= Block confounding in a factorial design
Partition a regular <factorial design> by fixed signs of <independent> <factorial contrasts>. Products of those block-generating columns span the <blocks in experimental design>[block] effects. A <treatment contrast> that is constant on each <blocks in experimental design>[block] is therefore confounded with <blocks in experimental design>[block] differences. Select generators so that only scientifically dispensable <treatment> effects enter this space; randomize the assignment of <blocks in experimental design>[blocks] and the run order within each <blocks in experimental design>[block].
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