Abstract—In an ever-increasing variety of contexts, people are working collaboratively to solve problems and accomplish tasks. Yet the characteristics of effectively functioning teams are not fully understood. We focus on the problem of identifying particularly effective teams in a large, complex, social-collaboration network. More specifically, given some task, and taking into account measures of both the effectiveness of an individual and the strength of the pairwise ties between individuals, can we identify the subgroup of people who are most likely to accomplish the said task? Our experimental work using DBLP data suggests that within any given subgroup, not all ties are of equal relevance. In fact, we show that focusing on the ties between one individual and the other group members – a star topology – will suffice. However, whereas the problem of finding the “best” subgroup is equivalent to MAX-CLIQUE and is thus hard to approximate, the problem of finding the best s...