  In the software engineering industry today, companies primarily conduct their
work in teams. To increase organizational productivity, it is thus crucial to
know the factors that affect team effectiveness. Two team-related concepts that
have gained prominence lately are psychological safety and team norms. Still,
few studies exist that explore these in a software engineering context.
  Therefore, with the aim of extending the knowledge of these concepts, we
examined if psychological safety and team norm clarity associate positively
with software developers' self-assessed team performance and job satisfaction,
two important elements of effectiveness.
  We collected industry survey data from practitioners (N = 217) in 38
development teams working for five different organizations. The result of
multiple linear regression analyses indicates that both psychological safety
and team norm clarity predict team members' self-assessed performance and job
satisfaction. The findings also suggest that clarity of norms is a stronger
(30\% and 71\% stronger, respectively) predictor than psychological safety.
  This research highlights the need to examine, in more detail, the
relationship between social norms and software development. The findings of
this study could serve as an empirical baseline for such, future work.
