Usability Engineering by Jakob Nielsen

More of reducing cognitive load through consistency, feedback, and path-dependency-awareness. Also, he notes that with one evaluator we typically catch 35% of the UI problems, while with five Eva Luators we snare 75%.

An interface should not look like an angry fruit salad
of wildly contrasting, highly saturated colors.
-- Usability Heuristics
Having access to an audit trail through the design rationale is important during iterative development and during any future releases of the product.
-- The Usability Engineering Lifecycle
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