We develop a novel moral hazard model of elections under closed- and open-list PR. Parties compete for legislative seats on the basis of their electoral output, which is a CES function of the effort choices of their candidates. Voters are well informed about these effort choices, or not. We show that, If effort choices are substitutable within parties, the cost of effort function is not too convex and voters are not well informed about the choices of individual politicians, closed lists generate higher electoral outputs than open lists. Our findings are robust to many extensions of the basic model, such as allowing for more than two parties, for ideological differences within the electorate, or for candidates to also care about their party winning control of the executive office.