Michael Weissman on The clustering of early cases around th…

Michael Weissman

Condensed-matter physicist, emeritus professor at the University of Illinois, who argues proximity ascertainment bias undermines the Huanan clustering inference.

[I]f the clustering of unlinked cases is due to proximity ascertainment bias, it contains no useful information about the source.

AI Verified (Feb 3, 2025)

Source:

Michael Weissman, University of Illinois (Substack)

3mo ago

Policy proposals and claims

The clustering of early cases around the Huanan market reflects where the COVID-19 virus emerged, not just where testing looked

votes Against

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AI Verified Relevant. In context, the article is explicitly addressing whether early-case clustering near the Huanan market indicates the outbreak source or instead reflects proximity ascertainment/testing bias, and this quote says that if bias explains the clustering, the clustering gives no useful information about the source. That makes a stance on the complete statement clearly determinable. ([michaelweissman.substack.com](https://michaelweissman.substack.com/p/big-news-on-covid-origins)) · YouCongress gpt-5.4-2026-03-05 · 3mo ago

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AI Verified Against: the quote says that if the clustering is due to "proximity ascertainment bias," it provides "no useful information about the source." In the article’s surrounding context, Weissman presents the Huanan-market clustering as potentially explained by ascertainment bias or neighborhood effects, not as evidence that the virus emerged there. ([michaelweissman.substack.com](https://michaelweissman.substack.com/p/big-news-on-covid-origins)) · YouCongress gpt-5.4-2026-03-05 · 3mo ago

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AI Verified The source URL is fetchable and shows the post "Big News on Covid Origins" by Michael Weissman dated Feb 03, 2025; the body text contains the exact sentence, "if the clustering of unlinked cases is due to proximity ascertainment bias, it contains no useful information about the source." The submitted form "[I]f ..." is a faithful bracketed capitalization change rather than a substantive alteration, so the quote is authentic and correctly attributed. ([michaelweissman.substack.com](https://michaelweissman.substack.com/p/big-news-on-covid-origins)) · YouCongress gpt-5.4-2026-03-05 · 3mo ago

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Michael Weissman votes Against

The clustering of early cases around the Huanan market reflects where the COVID-19 virus emerged, not just where testing looked

I showed that the latter theory at least gave the correct sign of the difference between the median distances from HSM to unlinked vs. to linked cases, while the Worobey model gave the wrong sign.

AI Verified source (Feb 3, 2025)

added 3mo ago

Michael Weissman votes For

COVID-19 originated from a lab-related incident rather than natural zoonotic spillover

What is most striking about Levin's results is that the unlinked case home address location-time pairs point rather strongly away from the HSM story unlike the common lore that they point extremely strongly toward the HSM story.

AI Verified source (Feb 3, 2025)

added 3mo ago

Michael Weissman votes For