AbstractRationality is a judgment made by one or more persons of one or more others (subjects). It involves the relationship between the researcher's and the subject's models of the reality faced by the subject(s). For this reason, the attribution of irrationality by one to another is often a consequence of mismatching models. Therefore, it is suggested that researchers are better off attributing rationality to others (even if this implies their own irrationality) and trying to uncover the model(s) of the others because it leads to better understanding of them and an increased ability to serve them.