First positive scoring and bout outcomes in adult male black-belt IBJJF gi and no-gi competition

Objective: To describe the proportion of first positive scorers who win adult male black-belt Brazilian jiu-jitsu bouts in gi and no-gi competition. Methods: Two availability-based cohorts of 800 IBJJF records per format were screened using provider-reconstructed score chronologies. Scoring ambiguities and no-positive-point records were retained in the study flow. Analyses included independent-bout reference intervals and exploratory sensitivities for repeated athletes, event families and calendar coverage. One reviewer reported full viewing of a random 200-bout audit after prior exposure to the classifications. Four uncertain first scorers were subsequently identified. Results: In the original source analysis, first scorers won 455/555 gi bouts (82.0%) and 424/488 no-gi bouts (86.9%). Adding four human adjudications yielded 455/556 (81.8%) and 427/491 (87.0%), respectively. Restricting the supplemented analysis to the common calendar window reduced the format difference to 2.1 percentage points, with an exploratory athlete-or-event interval of -4.1 to 8.3 points. Ninety-four records remained flagged in the full supplemented frame. Conclusions: First identified positive scorers won most eligible bouts. The format contrast was sensitive to calendar composition and does not establish a causal clothing effect. Review with prior label exposure cannot establish independent source accuracy. Preprint. Not peer reviewed. Both authors approved public dissemination under CC BY 4.0. Ethics, source limitations and AI assistance are disclosed in the manuscript.