This paper presents data that describe the effects on software develop
ment performance due to both the production methods of software develo
pment and the social processes of how software developers work togethe
r Data from 40 software development teams at one site that produces co
mmercial software are used to assess the effects of production methods
and social processes on both software product quality and team perfor
mance. Findings indicate that production methods, such as the use of s
oftware methodologies and automated development tools, provide no expl
anation for the variance in either software product quality or team pe
rformance. Social processes, such as the level of informal coordinatio
n and communication, the ability to resolve intragroup conflicts, and
the degree of supportiveness among the team members, can account for 2
5 percent of the variations in software product quality. These finding
s suggest two paradoxes for practice: (1) that teams of software devel
opers are brought together to create variability and production method
s are used to reduce variability, and (2) that team-level social proce
sses may be a better predictor of software development team performanc
e than are production methods. These findings also suggest that factor
s such as other social actions or individual-level differences must ac
count for the large and unexplained variations in team performance.