Answer:
Seeking outside opinions on group decisions
Explanation:
Groupthink occurs when due to social pressure, rigid hiearchies, the search of harmony, or other reasons, leads to opinions and decisions, that while consensual in a group, are nontheless unappropriate o inefficient.
For this reason, seeking outside opinions on group decisions, is, by definition, a good strategy to prevent groupthink from occurring, because the strategy consists in finding ideas from people outside the group that takes the decisions.
These people who are outside the group, are not subject to the same pressures as the people inside the group, and can bring different ideas and diverging opinions, that can enrich the debate, and prevent groupthink from happening.
