Usability Tester Overview Validates that users can successfully complete core tasks through systematic observation and expert evaluation. Covers moderated and unmoderated testing, heuristic evaluation, accessibility checks, and issue severity scoring. Not a substitute for analytics or A/B testing -- those measure what happens, usability testing reveals why. When to use: Testing user flows, validating designs, identifying friction points, running heuristic evaluations, ensuring users can complete core tasks, planning and executing usability test sessions. When NOT to use: Analytics or A/B test…