Estimator Recoverability, Not Numeric Carriage, Explains Estimator Reuse from Compressed Scientific Results

Scientific AI workflows increasingly pass results between models in compressed form: a reported estimate survives, while the analysis that produced it does not. When an upstream analysis used a flawed estimator and a downstream model later applies the same estimator to a new problem, it is tempting to conclude that the archived number carried the method. Yet recurrence alone cannot show this: the task, the reuse instruction, the presence of an artifact or the model's own prior can produce the same choice, and studies of answer cues lack the control that separates estimator-specific content from generic answer conditioning—a correct archived answer. We introduce matched-carrier attribution, which credits an archived wrong answer with carrying an estimator only if it induces that estimator on an independent new problem more often than every matched alternative, the correct answer included. We apply it to causal-effect estimation tasks in which a deterministic oracle identifies the estimator a model uses, and locate the mechanism with pre-registered interventions that edit one sentence of the artifact and leave the archived number unchanged. In Qwen3.5-27B, an archived wrong answer reliably leads the model to adopt the confounded estimator on new problems and exceeds all five controls. The effect disappears whenever the artifact no longer lets the estimator be identified, including when the quantity the number was computed from is replaced by a statistic of the same form that keeps the artifact complete, and this dependence replicates in a newer model generation, Qwen3.8-27B. Where the artifact never permits identification, as in meta-analysis, the number has no effect. Recoverability is necessary but not sufficient: when the model must end with a numeric estimate or declare the effect not identifiable, the effect shrinks in Qwen3.5-27B with the same dependence, and a second family, Mistral Small 3.2 24B, shows none. An archived number thus transmits a method not by itself but by letting the method be recovered from its context, which also means that a correct archive is not automatically safe.