Attack the Premise When two or more fixes that share one premise have failed the same gate, suspect the premise, not the fixes. Why: Each failed fix is evidence against the belief it assumed. A third fix on the same premise spends effort where the evidence already says the cause is not. Pattern: - Write the premise down. The premise is the one sentence that every failed fix assumed. - Test the premise before the next fix. Find an observation that would come out differently if the premise were false, and make it. Look at how the failures are distributed, not only at how large they are. Make th…