Journal of Functional Morphology and Kinesiology Article Playing in the UEFA Europa League Does Not Adversely Affect English Premier League or La Liga Performance Richard Stephens 1,* , Grant Bosworth 2 and Thomas A. Shepherd 2 1 Centre for Psychological Research, Keele University, Staffordshire ST5 5BG, UK 2 Research Institute for Primary Care and Health Sciences, Keele University, Staffordshire ST5 5BG, UK; [email protected] (G.B.); [email protected] (T.A.S.) * Correspondence: [email protected]; Tel.: +44-1782-736116 Received: 15 November 2018; Accepted: 19 December 2018; Published: 22 December 2018 Abstract: Purpose: This article presents data challenging the widely held but untested view that concurrently playing mid-week Union of European Football Associations (UEFA) Europa League matches adversely affects domestic league performance. Method: Over 16 seasons we compared next-season domestic league performance of the two highest finishing UEFA Europa League qualifying clubs with the two highest finishing non-qualifiers in England and Spain. Results: Clubs concurrently playing UEFA Europa League football showed significantly superior domestic league performance including wins, losses, goals, goal difference and points tally. The number of European matches played was not related to domestic league performance. Conclusions: The absence of prior rigorous analysis including appropriate comparison data has led to the proliferation of a widespread confirmatory bias, defined as the tendency to seek out evidence that backs one’s hunches and to ignore evidence that contradicts them. Based on our evidence, football professionals, journalists, pundits, and fans should consider the UEFA Europa League competition more favorably. Keywords: football; soccer; confirmatory bias; UEFA Cup; midweek matches 1. Introduction A compelling narrative has arisen in contemporary football (soccer) commentary around the alleged negative impacts on national domestic league performance of concurrently contesting the Union of European Football Associations (UEFA) Europa League competition [1]. Based on virtually no systematic analysis of data, the Europa League has been described as a ‘poisoned chalice’, a ‘secondary club competition’ and an ‘unwanted distraction’ from league football [2]. This is due to factors including additional fixtures in an already busy schedule, Saturday games being moved to Sundays to accommodate UEFA fixtures played on Thursday evenings, as well as increased risk of injuries and accumulated player fatigue [3,4]. Academic research has contributed towards the negative impact narrative. Cox, Gilmore and Graham report on a sample of four English Premier League (EPL) clubs that had played in the UEFA Europa League, a competition previously known as the UEFA Cup and henceforth referred to in this article as the UEFA EL/C, for two or more seasons from 2005-6 to 2012-3 [5]. They observed that three of these clubs finished in lower domestic league positions in seasons playing both competitions concurrently, compared with seasons when not. Furthermore, Verheijen, a football consultant, reports an analysis of 27,000 top flight games across seven countries and ten years, finding that clubs contesting the UEFA EL/C recoup an average of 1.27 points in domestic league matches played on Sundays after playing UEFA EL/C games on Thursdays, a lower average than the 1.68 points recouped, on average, J. Funct. Morphol. Kinesiol. 2019, 4, 2; doi:10.3390/jfmk4010002 www.mdpi.com/journal/jfmk J. Funct. Morphol. Kinesiol. 2019, 4, 2 2 of 9 for all domestic league games [6]. This indicates a deficit of 0.41 points per domestic league game following UEFA EL/C fixtures. While apparently supporting the negative impact narrative, both studies are limited, the former by a very small and unrepresentative sample and the latter by the absence of basic descriptive data such that means were presented in the absence of variance estimates. A further issue with both studies is the absence of an appropriate comparison or control condition. A fairer assessment of the impact of concurrent UEFA EL/C football on domestic league performance should compare clubs that are in the UEFA EL/C with clubs at a comparable domestic level that are not so engaged. As no such analysis has yet been undertaken, we remain skeptical that concurrently playing in the UEFA EL/C impacts negatively on domestic league form. Our skepticism was also aroused by data from prior studies showing that fixture congestion, defined as six matches in 21 days or three matches in four days, does not affect the physical and technical aspects of player performance [7]. Such congestion is associated with a higher rate of injuries [7] but, arguably, negative effects of injuries may be managed by ensuring adequate cover in the first team squad. We conducted the present study with the aim of providing a more critical analysis. Just as previous research has analyzed real world golf performance on the Professional Golfers’ Association tour [8] we found it relatively straightforward to identify and analyze online sources of data pertinent to domestic league performance in football. We included both the English Premier League (EPL) and the Spanish La Liga as each contains 20-member clubs and because these countries are ranked first and second with respect to performance in UEFA competitions [9]. However, we note the differences in the style of football played in these respective leagues, with the EPL characterized as having a “direct style” and La Liga characterized as being more “aesthetic” (with more emphasis on entertainment than results) combined with demanding “strong ball control” [10]. 2. Materials and Methods In England and Spain, between two and four clubs qualify for the UEFA EL/C each season. We compared EPL and La Liga performance of the two clubs placed highest the previous season that were concurrently playing UEFA EL/C football with that of the two highest-placed clubs that avoided UEFA EL/C and UEFA Champions League qualification. Usually the fifth and sixth placed clubs automatically qualify while the seventh placed club is able to qualify provided it wins its games in one or more preliminary rounds. This means that usually the two highest qualifiers finish fifth and sixth and the two comparison non-qualifiers finish seventh and eighth, or if the seventh placed club qualified through the preliminary rounds, eighth and ninth. However, some seasons deviate from this pattern. In 2003-04 Middlesbrough were the second qualifiers from eleventh place as League Cup winners. In 2004-05 the first and second qualifiers finished sixth and seventh because Liverpool qualified for the UEFA Champions League from fifth as winners the previous season. In 2010-11 Fulham were the second highest qualifiers from eighth position based on their UEFA Respect Fair Play ranking. In 2012-13 Swansea were the second highest placed UEFA EL/C qualifiers in ninth position as League Cup winners. In 2016-17 Arsenal were the second highest qualifiers from seventh position because Manchester United qualified for the UEFA Champions League from sixth as UEFA Europa League winners. Our analysis extended back over the last 16 seasons to reflect the modern game as much as possible while still providing sufficient data for our analyses to be meaningful. Data pertaining to league performance were obtained from the official websites of the Premier League [11] and La Liga [12]. For the full data set please refer to “UEFA Data CSV file.txt” in the Supplementary Materials. Data on managerial appointments, as well as UEFA EL/C qualification and games played were obtained from the worldfootball.net website [13]. This website is run by HEIM:SPIEL Medien GmbH & Co, a commercial company specializing in online sports data with customers including Sky Sports, FC Barcelona, and the Bundesliga [14]. As this study analyses data that is freely available and in the public domain, namely English and Spanish elite football league table data, formal Research Ethics Committee approval was not required. J. Funct. Morphol. Kinesiol. 2019, 4, 2 3 of 9 The main analyses consisted of a series of independent samples t-tests comparing, across the seasons 2002-03 to 2017-18, the two-highest placed UEFA EL/C qualifying clubs per season from the EPL (n = 32) versus the two-highest placed EPL clubs that avoided UEFA EL/C qualification (n = 32). The key dependent variables were wins, draws, losses, goals for, goals against, points tally and change in league position for domestic league football. We also examined two variables pertinent to in-season performance. The first was the number of changes of manager mid-season, between the dates of 1st July, to include pre-season, and mid-May. This was on the assumption that changing manager is an indication of response to crisis, and therefore that a higher number of managers is a negative outcome. The second was the total number of UEFA EL/C games played, on the assumption that playing a higher number of European games might disrupt domestic league performance. All analyses were subsequently repeated including the equivalent data from La Liga. 3. Results 3.1. Domestic League Performance Descriptive data are provided in Tables1 and2. Within the EPL there was one significant difference such that clubs concurrently playing UEFA EL/C and domestic football scored more domestic league goals than non-UEFA EL/C qualifiers, t (62) = 2.226, p = 0.030, d = 0.565, 95% CI = 0.614, 11.448. Combining the EPL and La Liga data we found that the UEFA EL/C qualifiers won more domestic league games, t (126) = 3.108, p = 0.002, d = 0.554, 95% CI = 0.789, 3.555, lost fewer games, t (126) = 2.240, p = 0.027, d = 0.399, 95% CI = −2.943, −0.192, scored more goals, t (126) = 3.854, p < 0.001, d = 0.687, 95% CI = 3.368, 10.476, had superior goal difference, t (126) = 3.167, p = 0.002, d = 0.564, 95% CI = 3.446, 14.929 and accrued more points, t (126) = 2.964, p = 0.004, d = 0.528, 95% CI = 1.963, 9.849, than non-UEFA EL/C qualifiers.