KNOWLEDGE NOTES

Knowledge Notes

Explore curated knowledge, course notes and methods, with their existing content and sources preserved.

This index lists complete English editions. Additional Chinese notes and bilingual updates remain available in the Chinese index.

350knowledge notes
Product Design & UX / NNGroup User Experience

NNGroup Qualitative Research and Research Methods Toolbox (Method Landscape / Interviews / Empathy Map / Sample Size / Task Design / Moderation / Expert Evaluation / Workshops / Ethics)

26 curated articles from Nielsen Norman Group's 'Qualitative Research' topic — effectively a complete UX research methods toolbox. Covers the four-quadrant method landscape (attitudinal what users say vs behavioral what users do × qualitative questions vs quantitative data, plus formative/summative/remote) and when to use which method; interviews (User Interviews 101 + the funnel technique: start broad and open, then narrow to closed questions, avoid leading too early); turning research into deliverables (Says-Thinks-Does-Feels empathy maps + user need statements: [User] needs [verb-based need] in order to [goal]); sample size (qualitative research relies on saturation, start with 5–6 participants and add dynamically; card sorting needs 15 people for r=0.90); usability task writing (qualitative open exploration vs quantitative single correct answer · randomization · dummy data); 10-step moderation checklist (say 'research' not 'test' + think-aloud protocol); expert evaluation without real users (3–5 independent evaluators for heuristic evaluation · cognitive walkthroughs assess learnability · 5-level severity rating · error message scoring rubric); UX workshops (meetings vs workshops · 5 types · 7 core activities · including users); research ethics (informed consent · screening criteria Inclusion-Exclusion-Diversity + recruitment matrix · 5 steps to democratizing research).

Qualitative researchUser interviewsUsability researchEnglish edition
Business & Entrepreneurship / Yitang Course Notes

Yitang / Complete System of Intelligence Research + Lean Experimentation

Complete notes for Yitang's 01 Entrepreneurship Required Course: "Intelligence Research" (5 docx + 13 PDF financial reports + Zhang Lei's nursing home data) + "Lean Experimentation" (4 docx). Covers ① OSCAR research model (initiated by Truman in 2018, third round of AI-powered upgrade in 2026) ② Research hacker systematic + exploratory arsenal ③ Expert interview + user interview SOPs ④ 13 real Hong Kong stock IPO prospectuses (Xiaomi/Meituan/Kuaishou/Nayuki/Xiaopeng/Trip/Baidu/Bilibili/Pop Mart/NetEase/New Oriental/Autohome/Jiumaojiu) ⑤ Lean startup — the six "worst" wastes + 4 principles + stripping assumptions + MVP design + systematic testing. Taught by Truman and Zhang Lei

Market researchUser interviewsLean experimentationEnglish edition