“…The term has also been applied in sociology and political economy (e.g., Wade, 2004), expressing that the rich get richer and the poor get poorer. 11 Note that in economics (e.g., Fehr & Schmidt, 1999) and sometimes also in marketing (e.g., Wangenheim & Bayón, 2007), the terms fairness and equity are used as synonyms, whereas this work follows the tradition of Deutsch (1975) who regards equity as one possible fairness principle among others (see Table 4). 12 Equity theory has stimulated a lot of research in the past decades, for example in organizational contexts (e.g., research on pay inequalities, Cowherd & Levine, 1992), in social relationships (e.g., Walster et al, 1973), and in marketing (e.g., Huppertz, Arenson, & Evans, 1978;Oliver & Swan, 1989;Wangenheim & Bayón, 2007).…”