  Incorporating fresh members in teams is considered a pathway to team
creativity. However, whether freshness improves team performance or not remains
unclear, as well as the optimal involvement of fresh members for team
performance. This study uses a group of authors on the byline of a publication
as a proxy for a scientific team. We extend an indicator, i.e., team freshness,
to measure the extent to which a scientific team incorporates new members, by
calculating the fraction of new collaboration relations established within the
team. Based on more than 43 million scientific publications covering more than
a half-century of research from Microsoft Academic Graph, this study provides a
holistic picture of the current development of team freshness by outlining the
temporal evolution of freshness, and its disciplinary distribution.
Subsequently, using a multivariable regression approach, we examine the
association between team freshness and papers'short-term and long-term
citations.The major findings are as follows: (1)team freshness in scientific
teams has been increasing in the past half-century; (2)there exists an
inverted-U-shaped association between team freshness and papers' citations in
all the disciplines and in different periods;(3)the inverted-U-shaped
relationship between team freshness and papers' citations is only found in
small teams, while, in large teams, team freshness is significantly positively
related to papers' citations.
