The impact of Mediterranean diet adherence on allergic diseases: a systematic review and meta-analysis.

For sports marketing in professional soccer, the question of how to interpret changes in fan behavior and loyalty is of paramount importance to the business model. Key performance indicators such as the number of season tickets sold or the development of membership numbers (and the corresponding retention rates) are considered important indicators of fan loyalty and engagement by many clubs. Optimizing ticketing (e.g., concerning the correct ration between season tickets and matchday tickets sold), reducing no-show rates among season ticket holders, and the efforts of many clubs to increase membership numbers () have recently received greater attention in both practical club operations and academic discourse. Against this backdrop, this article examines the extent to which two not uncommon phenomena—the return of season tickets and the termination of club memberships—can actually be considered valid indicators of declining loyalty and a fundamental shift away, or exit, from the club on the part of fans or supporters. This question is particularly relevant for sports marketing because the interpretation of these (and other) behavioral indicators influences decision-making in fan management. If cancellations of season tickets or memberships are interpreted solely as a sign of declining fan loyalty, clubs risk drawing incorrect conclusions about the stability of their fan base. A more nuanced analysis and interpretation of data in fan management, however, reveals that these decisions can be based on various motives or motive groups. These include, for example, negative evaluations of the stadium experience, scheduling conflicts due to match dates, or changes in fans' personal circumstances. Furthermore, normative factors, such as criticism of the commercialization of professional soccer, can play a role in making such decisions—a role that is not always immediately apparent. Considering these potentially diverse motives contributes to a more nuanced understanding of the dynamics of fan behavior in professional soccer and allows for more effective development of fan engagement strategies. If clubs accurately identify the reasons for cancellations, they are able to develop targeted, cause-oriented measures, such as improving the stadium experience or adapting ticket and membership models to the diverse life situations of fans. Insights into normative criticisms can reveal challenges that extend beyond individual clubs and are also relevant for stakeholders at the association level, for example, in the context of match scheduling or the perception of increasing commercialization in professional soccer. The paper is structured as follows: Section 2 () outlines the underlying model of the study, which is based on Hirschman's Exit-Voice-Loyalty Framework (), modified by Kaden et al. () to apply to soccer and its fan base. The (Section 3) then provides an overview of the current state of research on fan loyalty and exit behavior in professional soccer, including the consideration of season ticket ownership, club memberships, and causes of changes in fan behavior. Following this, Section 4 () discusses the data collection and analysis procedure based on a qualitative approach. The empirical findings are then presented in Section 5 () and systematically related to the underlying research question. In the subsequent (Section 6), the results are placed in a broader context while answering the research question. Concluding, management-related implications for the marketing of professional soccer clubs, limitations of the methodological approach, as well as theoretical implications and starting points for further research on fan behavior in professional sports are derived.