Article URL: https://maxghenis.com/mackenzie-scott-qaly/ Comments URL: https://news.ycombinator.com/item?id=48886311 Points: 52 # Comments: 21

How much health does $26.3 billion of philanthropy buy? Drag the assumptions and watch a Monte Carlo cost-effectiveness model rerun in your browser. Skeptical weights each effect by how well its study identifies causation. Credulous trusts every cited effect at face value. Central value (mode) of a 0.55–1.10 triangular draw for the share of the studied effect a marginal unrestricted grant delivers — the whole distribution is sampled, not this number alone. Real 2026 dollars. Default inflates each year's gifts ($26.39B nominal, 2020–2025) to ~$30.3B with CPI-U. The most important control is evidence stance: from skeptical (~70,000 QALYs — each effect weighted by how well its study identifies causation) to credulous (~200,000 — every cited effect at face value). That gap, not the dollar figure, is the real uncertainty. MacKenzie Scott's Yield Giving network has made over $26 billion in 2,700+ gifts since 2019 — $26.3 billion through 2025 by CNBC's year-end accounting. This page asks what that buys in quality-adjusted life-years, the unit health economists use to compare a death averted against years lived in better health. It is a GiveWell-style model: 13 intervention archetypes, each cost-per-QALY drawn where possible from a published causal estimate (Medicaid mortality, community health centers, supportive housing, collaborative-care depression), each effect shrunk toward zero in proportion to how well its study identifies causation, and the whole thing rerun through thousands of Monte Carlo draws each time you move a slider. I built the model with Claude; every estimate here is a model output, not a measured fact. The Python package, tests, and sources are on GitHub; this page runs a checked TypeScript implementation in the browser, reading the exported parameter file.