Consensus decision-making is a decision process that not only seeks the agreement of a majority of participants, but also to resolve or mitigate the objections of the minority (sometimes called the dissensus ) to achieve the most agreeable decision.
The method is intended to deemphasize the role of factions or parties and promote the expression of individual voices. The method also increases the likelihood of unforeseen or creative solutions by juxtaposing dissimilar ideas. Because it seeks to minimize objection, it is popular with voluntary organizations, wherein decisions are more likely to be carried out when they are most widely approved. Consensus methods are desirable when enforcement of the decision is unfeasible, such that every participant will be required to act on the decision independently. Minority views must be considered to a greater degree than in circumstances where a majority can take the action and enforce the decision without any further consultation with the minority voters. Since higher levels of consensus can require more time and effort to achieve, groups may reserve consensus decision methods for particularly complex, risky or important decisions.
Legitimate models of consensus exclude unanimous decisions and state clearly that unanimity is not consensus but rather evidence of intimidation, lack of imagination, lack of courage, failure to include all voices, or deliberate exclusion of the contrary views. For psychology of this see unanimity.
the full article on consensus decision making is here