I have written before that "day-of-week affects callback rate." That was based on a small sample and conventional wisdom. Last month I ran a properly-designed test with 200 real applications. The answer is messier than the conventional wisdom — and more useful. This post is the data and what to do with it. The setup 200 applications over 30 days. All senior backend engineering roles. Stratified across: Day of week: Mon/Tue/Wed/Thu/Fri (no weekends — too few JDs posted) Hour of submission: 7am–10am, 10am–1pm, 1pm–4pm, 4pm–7pm, 7pm–10pm (local recruiter time, US Pacific) Company tier: Tier-1 (FAANG-scale), Tier-2 (mid-cap public + late-stage private), Tier-3 (Series A-C), Tier-4 (seed / 50 employees) Same resume on every application. Same cover-letter template. Roles were genuinely different but matched the same skill profile. The only thing changing was when and where I clicked submit. The metric: did a human (recruiter or hiring manager) reach out within 14 days?…