We develop a conflict-oriented model of board task performance and argue that a common framework, that is, a shared understanding of its role, helps boards to perform well. Conflict is the mediating effect through which this plays out. We posit that a common framework increases board task performance because it reduces intragroup relationship conflicts, increases task conflicts within the board, and reduces conflicts in the relationship between board and CEO. We explore the model through a comparative participant observation study of 11 supervisory boards in action. The results show that while low levels of relationship conflict are typically considered a sign of a well-functioning board, the avoidance of relationship conflict negatively impacts board task performance and may lead to 'cognitive blindness'. Boards of directors should manage-rather than avoid-relationship conflict. Based on our findings, we suggest an extended model of conflict in boards that takes into account the negative effect of conflict avoidance.