Accountability is an important feature of effective teams, but many suppose that it is the team leader that needs to impose it. This traditional hierarchical approach denies the significant role that every member of a good team has in contributing to effectiveness by calling people on their deficiencies whilst being humble and open enough to be on the receiving end, too.
Poor performers need to feel pressure to improve and this can happen through a distribution of clear standards and agreements, especially ones into which everyone has had input. Also, regular reviews of progress encourage honesty and prompt an analysis of the factors that are and are not working, allowing positives as well as negatives to be highlighted. the positives can be enhanced with rewards (even small ones) which focus on the behaviour being sought. Leaders ultimately need to be enforcers so that morale doesn’t drop with the implied permission of poor standards, but great teams show the sort of discipline that enables everyone to consistently assess each other’s vital role in the overall pursuit of goals.