Accuracy and agreement of play the ball coding in rugby league

Play the ball (PTB) is an important tactical performance indicator in elite rugby league, referring to the action whereby a tackled ball carrier restarts play by rolling the ball underfoot to a teammate following a completed tackle. Despite its growing use in applied performance analysis, the accuracy of commercially coded PTB duration data has not been verified. This study aimed to assess the agreement between commercial and independently coded play the ball event durations from National Rugby League matches. A cross-sectional methodological design was employed using data from 1185 matches over six seasons (2018–2023). A stratified random sample of 372 PTB events was selected within eight standard deviation (SD) categories. Commercial coding of PTB duration was compared against independent coding with stopwatch during playback of official broadcast. Agreement was evaluated using intraclass correlation coefficients (ICCs), typical error of measurement (TEM), and Wilcoxon Signed Rank Tests for systematic bias. Agreement was poor for short-duration PTBs (<2.44 s; ICC = −0.03 to 0.32), with systematic underestimation by the commercial provider (e.g., < –3 SD: mean difference = −3.15 s; TEM = 2.51 s; p < 0.001). Agreement improved for moderate-to-long PTBs (≥2.48 s; ICC = 0.75–0.90), with strongest agreement observed in the 1–2 SD category (ICC = 0.90; TEM = 0.09 s; p = 0.60). Commercial PTB coding demonstrated acceptable agreement for moderate and longer durations but may misrepresent very rapid PTBs. Ongoing evaluation to ensure accurate PTB event coding is warranted given the importance of ruck speed in professional rugby league matchplay.