a study that involves two or more conditions or treatments in which each level of one condition or treatment is combined with each level of every other condition or treatment. For instance, a pharmaceutical treatment (Drug A vs. Drug B) may be combined with a biofeedback treatment (biofeedback vs. no biofeedback) so that each drug is combined with each type of biofeedback to form four possible interventions or treatment plans. The individual conditions being manipulated are known as crossed factors or crossed treatments. Also called crossed design.