This paper presents an empirical exploratory study involving 158 Swedish secondary school students (Years 7-11) asked to develop fair prescriptive mathematical models to rank real-life, multi-faceted heptathlon outcomes. A developed framework for identifying Characteristics of Fairness is used to investigate What types of models do the students develop? and What aspects of fairness in the context of heptathlon come to the fore in the students' models? Discussed and situated in relation to previous research, the result highlight and elaborate four identified types of models focusing on Event placement, Individual performance, Comparative performance and Baseline comparison. In particular the results show that students emphasised outcome fairness at the expense of process fairness. Based on the findings, implications and possible future lines of research and theoretical development are suggested.