Football clubs' efficiency and COVID-19 in the Big-5 European leagues

This study aims to contribute to the recent literature on the effects of COVID on football teams’ performance, focusing on the impact of playing behind closed doors – due to the health and safety measures following the COVID-19 pandemic outbreak - on offensive and defensive technical efficiency. Using a long season-level dataset for the top 5 European leagues, a novelty for efficiency studies on football, the analysis compares the ten seasons (2009-10 to 2018-19) played before the pandemic outbreak with the only season (2020-21) entirely played behind closed doors. The methodology applied to calculate the efficiency scores is the conditional order-m, whose application represents a further novel contribution to the literature on football teams’ efficiency. Our findings are consistent with the recent literature on the impact of ghost games on teams’ performance and show an erosion of the home advantage, likely due to the reduced pressure on visiting teams deriving from the lack of home crowd support

Do developers really worry about refactoring re-test? An empirical study of open-source systems

© Springer Nature Switzerland AG 2018. In this paper, we explore the extent to which a set of over 12000 refactorings fell into one of four re-test categories defined by van Deursen and Moonen; the ‘least disruptive’ of the four categories contains refactorings requiring only minimal re-test. The ‘most disruptive’ category of refactorings on the other hand requires significant re-test effort. We used multiple versions of three open-source systems to answer one research question: Do developers prefer to undertake refactorings in the least disruptive categories or in the most disruptive? The simple answer is that they prefer to do both. We provide insights into these refactoring patterns across the systems and highlight a fundamental weakness with software metrics trying to capture the refactoring process