But she did understand that they were doing factorial trials, altering the conditions in each pedon and tracking what happened.

Randomized double-blind factorial trial of three treatments to reduce the prevalence of precancerous gastric lesions.

The Third International Study of Infarct Survival (ISIS-3) was a 3x2 factorial trial that compared the three thrombolytic drugs streptokinase, tissue plasminogen activator (tPA) and anistreplase to each other, and also compared the anticoagulant heparin to no heparin.