NNGroup UX Research Method Selection (Quick Reference for 23 Methods / Four-Quadrant Positioning / Selection by Problem-Stage-Budget / Five Families: Qualitative Exploration, Quantitative Validation, Expert Evaluation, IA, Behavioral Analysis)
This collection covers 23 articles from Nielsen Norman Group's 'Research Methods' topic, positioned as a 'selection handbook' rather than a textbook — it answers 'which method should I use for my current problem'. It first places each method on NNGroup's classic four-quadrant framework (Attitudinal: what users say vs Behavioral: what users do × Qualitative: why vs Quantitative: how severe), then provides three sets of decision tables organized by problem type, project stage, and budget. The 23 methods are grouped into six families: ① Qualitative exploration (user interviews, focus groups, field studies, diary studies, task analysis) ② Quantitative behavior (analytics, conversion funnels, user path Sankey diagrams, eyetracking) ③ Controlled experiments (A/B testing, multivariate testing MVT) ④ Expert evaluation without real users (heuristic evaluation, cognitive walkthrough) ⑤ Information architecture IA (card sorting, tree testing) ⑥ Evaluation and synthesis (usability testing, root cause analysis RCA, Kano model, service blueprints, journey maps, visual design testing, reaction card emotion words). Each family includes guidance on 'when to use / how to choose / counterexamples'. It focuses on content not overlapping with the qualitative wiki: paired method chains (card sorting → tree testing → usability testing, interviews → diary studies → follow-up interviews, funnels → user paths → session replay → RCA), division of labor across the four quantitative methods, the path-dependency trap of A/B vs MVT, the five Kano categories and Better/Worse coefficients, and the finding that card sorting with 15 participants yields r=0.90. It overlaps with nngroup-qualitative-research by approximately 35% (in-depth coverage of interviews/focus groups/usability testing/expert evaluation appears there); this article only provides pointers to those and adds the 13 methods not covered in that piece.