OPSP: Oracle-Path Success Predictor for DTN Routing Efficiency

v4.0 (May 2026): Scopes OPSP as a sparse/slack-regime predictor and a binding-regime diagnostic. The paper now distinguishes the exact oracle-path product from the stronger empirical claim that the product predicts measured routing efficiency. A 584-case binding-regime survival test is added: direct OPSP has pooled R2 = 0.040 against measured efficiency, with no predictive skill in TTL-tight, congested, and retry-cascade regimes; the slack retry subset retains high skill (R2 = 0.912). The conclusion is revised accordingly: OPSP is a quantitative predictor in sparse or otherwise slack regimes, and a residual-generating diagnostic when deadline pressure, congestion, or retry cascades bind. The Oracle-Path Success Predictor (OPSP) computes DTN routing efficiency from the contact plan without Monte Carlo simulation. For each feasible injection time, the oracle traces a shortest path through the time-varying contact graph; OPSP is the mean product of hop success probabilities along those paths. The scoped interpretation is now explicit. OPSP is exact when the oracle path is the unique feasible path and is most useful as a predictor when retry and congestion dynamics do not bind. Outside those regimes, the signed gap between OPSP and measured routing efficiency remains useful as a topology diagnostic: positive gaps indicate dead-end tax, while negative gaps indicate path-diversity gain.