Which one of the following research findings is most consistent with the hypothesis that unions increase productivity?

A.  Other things equal, firm profits are lower where unions are present.
B.  Union workers receive, on average, higher fringe benefits relative to wages than nonunion
workers.
C.  The average amount of work time lost annually to strikes is surprisingly small.
D.  Labor turnover is less in unionized firms than in nonunionized firms.

ANSWER:

D