1. The study examined factors that affect ball retention at rucks in rugby union, such as the ratio of attacking to defending players and ball clearance times. 2. It found that attacking teams retained the ball more when they had two attackers for every defender, while committing fewer players or clearing the ball slowly increased chances of turnover. 3. Defending teams increased the likelihood of turnover by committing more players to slow ball clearance, but risked penalties if committing too many. Maintaining an even attacker-defender ratio resulted in turnovers without increasing penalty chances.