  While research continues to investigate and improve the accuracy, fairness,
and normative appropriateness of content moderation processes on large social
media platforms, even the best process cannot be effective if users reject its
authority as illegitimate. We present a survey experiment comparing the
perceived institutional legitimacy of four popular content moderation
processes. We conducted a within-subjects experiment in which we showed US
Facebook users moderation decisions and randomized the description of whether
those decisions were made by paid contractors, algorithms, expert panels, or
juries of users. Prior work suggests that juries will have the highest
perceived legitimacy due to the benefits of judicial independence and
democratic representation. However, expert panels had greater perceived
legitimacy than algorithms or juries. Moreover, outcome alignment - agreement
with the decision - played a larger role than process in determining perceived
legitimacy. These results suggest benefits to incorporating expert oversight in
content moderation and underscore that any process will face legitimacy
challenges derived from disagreement about outcomes.
