---
conjecture: r2-edh-b1-11
family: codex
model: "gpt-5.6-sol (codex-cli 0.144.0-alpha.4, ChatGPT-subscription auth)"
model_stamp_corrected: "2026-08-07 — archives were first written stamped gpt-5.5 by a runner bug (the stamper read config.toml's default instead of the -m flag actually passed). The calls themselves ran on gpt-5.6-sol throughout; only the label was wrong. Corrected in place, noted here rather than silently."
received: 2026-08-07
template: PROMPT_TEMPLATE_v1.md sha256 4344aabfacfe88362c56d89b6c89d594a7bf3a221e18a16b0e351482447e512f
rivals_parsed: 3
validation: VALID
---

{
  "rivals": [
    {
      "mechanism": "The provincial ratios may be generated by clustered catalogue ingestion: a few excavated instrumentum assemblages or specialized publications can contribute many separately counted fragments or stamp instances. This creates high row percentages without a province-wide concentration caused by frontier military production.",
      "why_it_explains_the_same_evidence": "Rhine provinces, the successful holdout province, and the high non-frontier provinces could each contain one or more heavily harvested instrumentum corpora, while the 6.52% province lacks such a corpus. An alphabetical holdout does not control for source-level clustering, and the comparable non-frontier rates fit this mechanism particularly well.",
      "named_confounds": [
        "bibliographic-source harvest effects",
        "pseudoreplication of fragments or repeated stamp instances",
        "uneven excavation and publication coverage"
      ],
      "discriminating_test": {
        "description": "Measure how numerator rows are distributed across findspots, bibliographic sources, and normalized stamp texts. Recompute provincial percentages after collapsing rows sharing a findspot, source, and normalized stamp, and perform leave-one-findspot and leave-one-source-out analyses. The military-frontier mechanism predicts a comparatively broad distribution across multiple frontier sites; the harvest mechanism predicts strong concentration and large ratio changes when a few clusters are collapsed or removed.",
        "computable_on_held_data": true,
        "what_result_favors_rival": "The 17.28% result and the Rhine rates become substantially smaller or unstable after cluster collapse, with most stamped rows attributable to a handful of findspots, publications, or repeated stamp forms."
      }
    },
    {
      "mechanism": "Regional fired-clay construction and stamping by civilian, municipal, or imperial workshops may drive the pattern rather than legionary frontier supply. Provinces containing major building programs, production centers, or settlements using stamped brick, tile, and pipe would then have high instrumentum shares regardless of frontier status.",
      "why_it_explains_the_same_evidence": "The reported outcome distinguishes object types but not their producers or archaeological contexts. Civilian construction intensity could therefore produce the Rhine highs and the 17.28% holdout value, while variation in building practice could leave the other target at 6.52%; comparable non-frontier training rates are expected under this mechanism.",
      "named_confounds": [
        "civilian versus military producer misattribution",
        "regional construction-material traditions",
        "settlement and building-program composition"
      ],
      "discriminating_test": {
        "description": "Classify the stamp texts as explicitly military, explicitly civilian or private, civic or imperial non-military, or indeterminate, then recompute each province's percentage using only stamps that unambiguously name a legion, cohort, or other military unit. The stated mechanism predicts that high frontier percentages are disproportionately composed of explicit military stamps; the rival predicts that the aggregate highs are mainly civilian or non-military and disappear when the numerator is military-restricted.",
        "computable_on_held_data": true,
        "what_result_favors_rival": "The successful province remains high for all portable stamps but has no elevated rate of unambiguously military stamps, with most classifiable numerator rows naming non-military producers or institutions."
      }
    },
    {
      "mechanism": "Province-specific completeness of monument-type metadata may manufacture the percentage. If stamped portable objects are reliably assigned a monument type while ordinary inscriptions are disproportionately left untyped in certain catalogue batches, restricting the denominator to monument-typed rows inflates the instrumentum share.",
      "why_it_explains_the_same_evidence": "Shared metadata practices could inflate all three Rhine provinces and the successful holdout province, while more complete typing could yield 6.52% in the other target. The similarly high non-frontier provinces are also naturally explained because metadata completeness need not follow military geography.",
      "named_confounds": [
        "differential monument-type missingness",
        "province-specific data-entry practice",
        "denominator selection from typed rows"
      ],
      "discriminating_test": {
        "description": "Measure monument-type missingness by province and bibliographic source, recompute the numerator over all otherwise eligible EDH rows, and separately recompute it within source strata having near-complete monument typing. A standardized or imputed analysis can equalize typing completeness across provinces. Genuine frontier concentration should remain visible under these denominators; the metadata mechanism predicts that the high ratios track missingness and shrink after standardization.",
        "computable_on_held_data": true,
        "what_result_favors_rival": "High provincial percentages strongly correlate with monument-type missingness, and the successful province no longer clears 10% or ceases to be elevated when all eligible rows or only completeness-matched source strata are used."
      }
    }
  ],
  "no_viable_rival": false,
  "notes": ""
}
