Their main findings are:[1] Later experiments lead to different conclusions: Benade, Itzhak, Shah, Procaccia and Gal compared input formats on two dimensions: efficiency (social welfare of the resulting outcomes), and usability (cognitive burden on the voters).
They concluded that k-approval voting imposes low cognitive burden and is efficient, although it is not perceived as such by the voters.
Their goal was to maximize social welfare by using observed votes as proxies for voters’ unknown underlying utilities.
[3] Fairstein, Benade and Gal report the results of an experiment with Amazon Turk workers, on a PB process in an imaginary town.
[4] Yang, Hausladen, Peters, Pournaras, Fricker and Helbing constructed an experiment modeled over the PB process in Zurich.
[6] Fairstein, Benade and Gal compared the robustness of various methods to the participation rate, that is: if a certain random subset of the voters remain at home, how does it affect the final outcome?
They found out that greedy outcomes are highly sensitive to the input format used and the fraction of the population that participates.