Remember, that an issue with within-subjects designs is that subjects usually contribute data to each condition at different times or orders in the experiment. As a result, the order of the manipulation, rather than the manipulation itself, can sometimes cause differences. Counterbalancing is a technique used to systematically control the order in which subjects receive the manipulation.

Ya know, someday these scientists are gonna invent something that will outsmart a rabbit —Bugs Bunny Hewwo! Acme Pest Contwol? Weww I have a pest I want contwolled. —Elmer Fudd Elmer Fudd is always being outsmarted by Bugs Bunny. If Elmer Fudd was a psychologist, he might say “Be vewy vewy quiet, I’m conducting an expewiment”. But, we all know how the experiment would turn out. Bugs Bunny would find a way to foil Elmer Fudd’s plans and ruin his experiment.

An efficient way of counterbalancing is through a Latin square design which randomizes through having equal rows and columns. For example, if you have four treatments, you must have four versions. Like a Sudoku puzzle, no treatment can repeat in a row or column. For four versions of four treatments, the Latin square design would look like the table to the right.