We investigate whether and how social ties affect performance in teams by implementing a field experiment in which a sample of undergraduate students are randomly assigned to either teams composed by friends or teams composed by individuals not linked by friendship relationships. Students...

Do contributions to online content platforms induce a feedback loop of ever more user-generated content or will they discourage future contributions? To assess this, we use a randomized field experiment which added content to some pages in Wikipedia while leaving similar pages unchanged. We find...