Predictable Information in Galaxy Rotation-Curve Discrepancies: A Population-Level Inquiry

The galaxy rotation-curve discrepancy is one of the most persistent empirical tensions in modern astrophysics. This study binds the tension to a prior question: does the discrepancy itself contain predictable information? Therefore, using 175 individual SPARC galaxy files containing 3,391 radial measurements, we calculate the direct signed discrepancy between the observed and baryonic contributions, retaining its positive and negative branches, and concentrate on the positive branch. A primary population of 166 galaxies (3,214 measurements) is represented by ΔV²(r)=B+Cr. The coefficients show substantial radial organization. The main empirical result is that measurable population information can be used to predict the known discrepancy in any galaxy (i.e., being excluded) using information that was not used to construct the population relationship (from that excluded galaxy). The analysis begins with the complete 175-galaxy SPARC dataset and proceeds in two tracks. The empirical track follows along: observation → baryonic contribution → signed discrepancy → radial structure → population prediction → blind reconstruction. The interpretive track then injects fundamental inquiry and asks what it means if the discrepancy contains organized information not explicitly represented in the observable baryonic description. The observations that encompass the dataset capture a deeply consistent and diverse range of galactic information. Nine structurally distinct systems, identified as anomalous by quantitative criteria and visual inspection, remain part of the observational dataset but are screened from the primary population representation; they are not treated as erroneous measurements, they are simply sequestered.The present paper explicitly separates empirical predictability from physical interpretation. The strict LOGO result is the primary benchmark, and the modified LOGO (grouped hold-out) analysis tests whether that result depends on the informational content of the blindly selected inquiry galaxies.