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In the same 2026 Roman–Byzantine trade-network study
([[claim-roman-byzantine-trade-network-decoupled-after-1082-chrysobull]]), the
authors catch their own method producing a *false* signal. When a break-detection
statistic is computed on a subgraph built by sampling only the highest-degree
("hub") nodes of a degree-heterogeneous historical network, the inferred trend
becomes non-monotonic in sample size: per the capture's full-text read, "N=800
top-degree sampling produces lower Chow F-statistics than both N=400 and N=1,600."
The abstract states the consequence directly — a "hub-selection artifact in
degree-heterogeneous networks can reverse the sign of the inferred Phase III
slope." The cause is that Western hubs dilute inter-regional cycle structure, so
which hubs land in the sample determines whether a breakpoint appears at all.

The authors' fix is a **minimum-coverage sampling rule** that preserves regional
representation ratios rather than sampling by degree alone — an explicit,
pre-specified guard against the artifact.

The general shape — *a striking pattern mined from a large structured dataset may
be an artifact of how the data was sampled, not a real signal* — recurs across
domains the vault already tracks. It is the same worry behind
[[claim-bridge-detection-lacks-pkg-validation]] (whether a graph "bridge" signals
a real knowledge gap or a structural accident) and
[[claim-structural-gaps-not-modularity-score-are-gap-signal]] (which network
measure actually carries the signal). See [[moc-knowledge-gap-detection]]. Its
messier, unresolved twin in quantitative history is
[[claim-seshat-moralizing-gods-finding-disputed-as-data-artifact]].

> [!note] Seek's commentary:
> Three unrelated fields — ancient-trade topology, this vault's own
> knowledge-graph tooling, and the historians-vs-cliodynamicists feud —
> independently hit the same epistemic anxiety. The physicists engineered around
> it in a robustness section because a spurious F-statistic is falsifiable and
> embarrassing in your own preprint; cliodynamics is still fighting about it in
> public. Same disease, different immune systems. If a fourth independent
> instance surfaces, this cluster wants an MOC on "pattern vs. sampling
> artifact." — Seek