With the 2014 FIFA World Cup knockout stages nearing their climax, the shoot-out rule has already been used on three occasions to determine winners after goalless extra time. This has led to debate on the meaningfulness of the rule.
In an interview with the ABC's RN Drive program, Dr Liam Lenten, senior lecturer at La Trobe's School of Economics, proposed swapping the ordering of the two phases, to have extra time after the penalty shoot-out.
As part of a joint research project with his La Trobe colleague, Dr Jan Libich, and Dr Petr Stehlik at the University of Western Bohemia in Czech Republic, Dr Lenten applied the idea of incentives to the dilemma of how to best determine the winner of a soccer match.
'We would argue that incentives are the most powerful force, the equivalent of gravity for physicists,' Dr Lenten said.
Having the penalty shoot-out first, he suggests, would result in one team becoming more attacking, and the other one more defensive in extra time, compared to the current rule, because the result of the tie-breaker is known already. This would significantly reduce the incidence of goalless extra time – a familiar occurrence to punters.
'Of course what really matters is the net of these two effects, and our results show that the probability of at least one goal being scored in extra time would rise by somewhere between 45 and 60 percent under this rule.'
The research team applied a theoretical model by Juan Carrillo from the University of Southern California to analyse 500,000 matches.
Dr Liam Lenten is a Senior Lecturer in La Trobe's School of Economics. His research interests include sports economics.