  Participants in socio-economic systems are often ranked based on their
performance. Rankings conveniently reduce the complexity of such systems to
ordered lists. Yet, it has been shown in many contexts that those who reach the
top are not necessarily the most talented, as chance plays a role in shaping
rankings. Nevertheless, the role played by chance in determining success, i.e.,
serendipity, is underestimated, and top performers are often imitated by others
under the assumption that adopting their strategies will lead to equivalent
results. We investigate the tradeoff between imitation and serendipity in an
agent-based model. Agents in the model receive payoffs based on their actions
and may switch to different actions by either imitating others or through
random selection. When imitation prevails, most agents coordinate on a single
action, leading to non-meritocratic outcomes, as a minority of them accumulates
the majority of payoffs. Yet, such agents are not necessarily the most skilled
ones. When serendipity dominates, instead, we observe more egalitarian
outcomes. The two regimes are separated by a sharp transition, which we
characterise analytically in a simplified setting. We discuss the implications
of our findings in a variety of contexts, ranging from academic research to
business.
