Background: Leg-before-wicket (LBW) dismissals in cricket require exacting visual judgements by umpires, a task complicated by the requirement to also adjudicate on where the bowler's front foot is relative to the popping crease line about the time the ball leaves the bowler's hand. The umpire must then judge as soon as possible afterwards whether the direction of the flight of the ball is in line with the batsman's stumps. This study investigated whether the accuracy of cricket umpires' decision-making in leg-before-wicket dismissals is affected by varying the method by which umpires monitor bowlers' feet at the point of delivery of the ball.
Methods: Four umpires officiating under simulated match conditions reported their judgements of whether each delivery they observed pitched in line with the stumps. They did so under one of three conditions: watching the bowler's front foot, watching the bowler's back foot prior to the delivery of the ball by the bowler or not monitoring the bowler's feet ('no foot' condition). Video recording, assisted by the use of superimposed stump-to-stump lines, was used to assess the accuracy of the umpires' responses.
Results: There was no statistically significant difference in umpires' performance when comparing the front foot condition to the back foot condition but performance for the 'no foot' condition was significantly better than for the front foot condition.
Conclusions: These results suggest that umpires' performance judging LBW dismissals would be improved if they did not have to monitor bowlers' feet to adjudicate 'no-ball' deliveries but there would be no benefit from a reversion from the current 'front foot' no-ball law to the previously used back foot law.