Table_1_Coach Turnover in Top Professional Brazilian Football Championship: A Multilevel Survival Analysis.DOCX

In this study, we examined the probability of coaches’ survival in the top Brazilian professional football championship considering variation across the competitive seasons between 2012 and 2017, considering a multilevel framework. We also considered whether previous coaching experience in the top Brazilian professional football championship would change the probability of coaches’ survival across the season. The data considered 4,560 games from the top professional Brazilian football league (Campeonato Brasileiro Série A) between the 2012 and 2017 seasons. At the start of each season, the coach from each team was followed, being recorded at the time the event occurred, i.e., the coach being sacked. A total survival of 120 coaches was considered between the seasons of 2012 and 2017, i.e., 20 coaches at the beginning of each season. Coaches were assigned as novice (no previous experience as head coach in the top Brazilian championship) or experienced (with at least some previous experience as head coach in the top Brazilian championship). Data were available and extracted from the official website of the Brazilian Football Confederation1. On average and considering un-pooled observations, the median life of a coach was about 16.5 rounds. Considering variation between 2012 and 2017 seasons, only about 26.3% (95% CI: 18.2–36.1) of the coaches ended a season without being sacked. By mid-season, at round 19, the probability of coaches’ survival was 0.42 (95% CI: 0.32–0.53). Variation between season on survival estimates per round was substantial (between-season standard deviation = 0.48, 95% credible intervals: 0.25–0.95; corresponding to an inverse logit = 0.62, 95% CI: 0.56–0.72). There was no substantial variation between novice and experienced coaches’ survival probability. The present results expose the vulnerability of the coaching context in Brazilian football, potentially highlighting an excessive emphasis on short-term results to mediate club management decisions.

本研究采用多层分析框架，考察2012至2017年间巴西顶级职业足球联赛各赛季差异下，主教练的执教存续概率。同时探讨主教练过往在巴西顶级职业联赛的执教经历，是否会改变其当季的执教存续概率。本研究所用数据取自巴西足球联合会（Brazilian Football Confederation）官方网站¹，涵盖2012至2017赛季巴西足球甲级联赛（Campeonato Brasileiro Série A）的4560场赛事。本研究追踪每赛季开赛时各球队的主教练，记录其下课事件的发生时间，即主教练被解雇的时刻。2012至2017赛季共计120名主教练纳入分析，即每赛季初始时有20名主教练参与研究。主教练被分为两类：新手型（未在巴西顶级职业联赛担任过主教练）与经验型（曾在该联赛拥有至少一次主教练任职经历）。基于未合并观测的平均分析显示，主教练的中位执教时长约为16.5轮。对比2012至2017赛季的差异，仅约26.3%（95%置信区间：18.2–36.1）的主教练能够完整执教完一个赛季而未被解雇。在赛季中期第19轮时，主教练的执教存续概率为0.42（95%置信区间：0.32–0.53）。不同赛季间的执教存续率轮次差异显著（赛季间标准差=0.48，95%可信区间：0.25–0.95；对应逆logit值为0.62，95%置信区间：0.56–0.72）。新手型与经验型主教练的执教存续概率无显著差异。本研究结果揭示了巴西足球主教练岗位的脆弱性，或可反映俱乐部管理决策中过度强调短期业绩的倾向。