Reproducibility Artifact for Platform Adaptation Under Governance Interventions: Actor Best-Response Modeling and an External Public-Case Benchmark

This reproducibility artifact accompanies the paper Platform Adaptation Under Governance Interventions: Actor Best-Response Modeling and an External Public-Case Benchmark. It combines the benchmark evidence and supporting source materials into a single auditable archive. The main evidence layer contains 72 external public platform-governance cases evaluated across 9 methods, producing 648 method-case score rows and 360 action-score rows. The archive includes the platform-adaptation rubric, public source manifest, benchmark runner and validator, row-level method and action scores, aggregate results, bootstrap confidence intervals, paired comparisons, domain summaries, failure analysis, verification metadata, shared schemas, construct-validity protocol, significance statement, managerial-implications documentation, manuscript source snapshot, provenance records, and a SHA-256 integrity manifest. The benchmark evaluates whether governance-evaluation methods identify actor best responses, strategic gaming opportunities, moderation burden, user-incentive shifts, enforcement responses, externality formation, and downstream platform stability after governance interventions. All cases in the main evidence layer are externally grounded public cases with source URLs; synthetic cases are not used as the principal evidence. The artifact supports a bounded mechanism-recovery claim rather than exact prediction of realized platform outcomes or a private platform-log field experiment.