Structural predictors of analytical fragility in social science: evidence from SCORE Multi100

The SCORE Multi100 programme assigned four to seven independent analysts to each of 100 published social and behavioural science papers, producing 508 analyst-paper rows, a mean paper-level strict agreement rate of 0. 36, and 64 fragile papers (a<0. 5). The paper-level distribution of agreement is starkly bimodal: the 64 fragile papers coincide exactly with the 64 papers satisfying a≤0. 2, and no paper lies in the open interval (0. 2, 0. 8) ; a two-component Gaussian mixture beats a unimodal fit by ΔBIC ≈ 1190. From a pre-specified predictor set, two structural correlates of fragility survive the paper's primary inferential standard. Log sample size correlates positively with agreement at paper resolution (Spearman ρ = 0. 22, p = 0. 034, n = 93), and a transparency-fragility paradox emerges in which high-badge papers show higher fragility than low-badge papers (means 0. 286 vs. 0. 552, Mann-Whitney p = 0. 013; paper-level fragility odds ratio OR = 2. 86, 95% CI 1. 18, 6. 92, p = 0. 020). The row-level TotalHours effect (ρ = 0. 11, p = 0. 018) attenuates under analyst-clustered robust standard errors, where no row-level predictor reaches α = 0. 05. A pre-specified null on ||z|-1. 96| (ρ = -0. 04, p = 0. 69) guards against selective reporting. A cross-validated multivariate logistic classifier attains paper-level AUC = 0. 667 ± 0. 167 (n = 63) and row-level GroupKFold AUC = 0. 625 (n = 474), well above chance but well below ceiling on 100 papers. Methodology note: the manuscript was produced end-to-end by an autonomous multi-agent research system, architected and operated by the sole human author, who takes full responsibility for all content. The replication archive (OSF DOI 10. 17605/OSF. IO/TJEHY) contains the pre-specified analysis plan, evidence manifest, scripts, and SHA-256-anchored data.