We analyze the relationship between partisanship, echo chambers, and
vulnerability to online misinformation by studying news sharing behavior on
Twitter. While our results confirm prior findings that online misinformation
sharing is strongly correlated with right-leaning partisanship, we also uncover
a similar, though weaker trend among left-leaning users. Because of the
correlation between a user’s partisanship and their position within a partisan
echo chamber, these types of influence are confounded. To disentangle their
effects, we perform a regression analysis and find that vulnerability to
misinformation is most strongly influenced by partisanship for both left- and
right-leaning users.