Context-Gain Concentration Is Not Evidence Of Routable Forecast Value

A steep context-gain concentration curve is not evidence that context value can be routed. Ranking forecast origins by realized gain and summing those same gains selects favourable noise, so the curve can rise steeply even when conditional value is identical at every origin. We define context value at an origin and horizon and apply a two-leg rule frozen after method development: the constant-value null leg tests whether a prespecified rank-transition signature in realized gains is incompatible with a fitted dependence- and scale-preserving null, and the held-out predictability leg asks whether realized gain can be ranked out of sample. The composed rule is validated against known truth before empirical evaluation. The strict conjunction supports 5 of 9 domain–backbone pairs, covering energy and retail but not finance/news. It was evaluated once on the designated analysis folds. These results support the prespecified transition signature together with held-out rank predictability in the supported pairs, not context-gain concentration or a general routing premise.