---
conjecture: r2-edh-b1-25
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 recorded extremes may arise from inconsistent use of the explicit 'no image' marker across data-entry cohorts, contributors, or legacy imports rather than from differences in actual photographic documentation. Some cohorts may leave the field blank when no image exists, while others explicitly mark absence.",
      "why_it_explains_the_same_evidence": "If provinces are concentrated in different contributor or import cohorts, their measured rates can range from 0% to above 50% even when their actual image availability is similar. Because the alphabetical split does not balance data-entry cohorts, the same coding artifact can generate extremes in both training and holdout provinces.",
      "named_confounds": [
        "inconsistent missing-image coding",
        "legacy-import or data-entry-cohort effects",
        "measurement based on an explicit absence flag rather than verified image presence"
      ],
      "discriminating_test": {
        "description": "For every eligible record, independently determine whether a resolvable image, thumbnail, or media link actually exists, then cross-tabulate verified availability against the explicit 'no image' marker and identifiable contributor or import cohorts. Recompute province rates using verified image presence and fit models with cohort and province effects.",
        "computable_on_held_data": true,
        "what_result_favors_rival": "The rival is favored if marker sensitivity or specificity differs sharply by cohort and the province extremes substantially shrink or disappear when coverage is measured from actual media assets or adjusted for entry cohort."
      }
    },
    {
      "mechanism": "Image availability may be driven chiefly by the physical and historical composition of each province's catalogued inscriptions, such as the share of objects that are lost, unlocated, reused, inaccessible, fragmentary, or known only from old publications. Provinces would then differ because their catalogued objects have different photographability, not because documentation effort was resourced differently.",
      "why_it_explains_the_same_evidence": "A province dominated by lost or historically recorded objects could exceed 40% without images, whereas one dominated by extant, accessible excavation material could approach 0%. Such object-status mixtures can occur in both alphabetical halves, so the held-out reproduction follows without a province-level resourcing mechanism.",
      "named_confounds": [
        "survival and preservation bias",
        "present-location or accessibility status",
        "object-type and discovery-era composition",
        "selection effects in which inscriptions were catalogued"
      ],
      "discriminating_test": {
        "description": "Classify records by extant versus lost status, whether the present location is known, object or inscription type, and discovery or publication era. Compare provinces within matched strata and standardize every province to a common composition, then test whether substantial province residual effects remain.",
        "computable_on_held_data": true,
        "what_result_favors_rival": "The rival is favored if no-image status is strongly predicted by object survival and accessibility variables and the standardized province rates no longer reproduce the greater-than-40% and less-than-3% extremes."
      }
    },
    {
      "mechanism": "Modern holding institutions may differ in image-release, copyright, access, or digitization policies, with ancient province acting only as a proxy because objects from a province are often concentrated in particular museums or repositories. The causal unit would be the present repository rather than the province or provincial documentation budget.",
      "why_it_explains_the_same_evidence": "Repositories that routinely supply reusable images can make their associated provinces appear nearly complete, while institutions that restrict access or lack transferable image rights can produce rates above 40%. Since institution-province concentration is unrelated to the alphabetical train-holdout split, both halves can contain an extreme institution and therefore an extreme province.",
      "named_confounds": [
        "present-repository concentration",
        "institutional image-rights policy",
        "museum access and digitization policy",
        "ancient-province versus modern-custodian classification mismatch"
      ],
      "discriminating_test": {
        "description": "Group records by present holding institution and fit a cross-classified model containing both repository and ancient-province effects. For repositories holding inscriptions from multiple provinces, compare no-image rates across those provinces; also compare a province's records across multiple repositories.",
        "computable_on_held_data": true,
        "what_result_favors_rival": "The rival is favored if repository effects dominate, rates are similar across provinces within the same repository, and province effects or threshold-crossing extremes largely vanish after adjustment for present custodian."
      }
    }
  ],
  "no_viable_rival": false,
  "notes": "The aggregate replication establishes heterogeneity in the recorded measure, but by itself does not identify whether the causal level is province, record composition, repository, or data-entry process."
}
