With the agile approach to managing software development projects comes an
increased dependability on well functioning teams, since many of the practices
are built on teamwork. The objective of this study was to investigate if, and
how, team development from a group psychological perspective is related to some
work practices of agile teams. Data were collected from 34 agile teams (200
individuals) from six software development organizations and one university in
both Brazil and Sweden using the Group Development Questionnaire (Scale IV) and
the Perceptive Agile Measurement (PAM). The result indicates a strong
correlation between levels of group maturity and the two agile practices
\emph{iterative development} and \emph{retrospectives}. We, therefore, conclude
that agile teams at different group development stages adopt parts of team
agility differently, thus confirming previous studies but with more data and by
investigating concrete and applied agile practices. We thereby add evidence to
the hypothesis that an agile implementation and management of agile projects
need to be adapted to the group maturity levels of the agile teams