  Participatory Budgeting (PB) is a process in which voters decide how to
allocate a common budget; most commonly it is done by ordinary people -- in
particular, residents of some municipality -- to decide on a fraction of the
municipal budget. From a social choice perspective, existing research on PB
focuses almost exclusively on designing computationally-efficient aggregation
methods that satisfy certain axiomatic properties deemed "desirable" by the
research community. Our work complements this line of research through a user
study (N = 215) involving several experiments aimed at identifying what
potential voters (i.e., non-experts) deem fair or desirable in simple PB
settings. Our results show that some modern PB aggregation techniques greatly
differ from users' expectations, while other, more standard approaches, provide
more aligned results. We also identify a few possible discrepancies between
what non-experts consider \say{desirable} and how they perceive the notion of
"fairness" in the PB context. Taken jointly, our results can be used to help
the research community identify appropriate PB aggregation methods to use in
practice.
