What does it mean to arrive at a decision?
By Patrick Edwin Moran (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons
If you make a decision following a coherent process then you can arrive at a best decision by a process of elimination. An example could be the use of decision theory where an individual uses a coherent process to arrive at an optimal decision.
The area of choice under uncertainty represents the heart of decision theory. Known from the 17th century (Blaise Pascal invoked it in his famous wager, which is contained in his Pensées, published in 1670), the idea of expected value is that, when faced with a number of actions, each of which could give rise to more than one possible outcome with different probabilities, the rational procedure is to identify all possible outcomes, determine their values (positive or negative) and the probabilities that will result from each course of action, and multiply the two to give an "expected value", or the average expectation for an outcome; the action to be chosen should be the one that gives rise to the highest total expected value.
Realistically it is not likely that an individual can make high quality decisions consistently by themselves by consistently following a coherent process like decision theory. Particularly because it is a lot of calculations and eventually a decision will be too complex for the typical individual to calculate. An additional problem is information scarcity where the individual simply doesn't have access to all the information. How can an individual overcome information scarcity?
Decision by committee as a way of overcoming information scarcity
If an individual doesn't make each decision by themselves but instead by a trusted committee and the committee in theory has greater access to information than any individual by themselves then the decision quality likely will be enhanced.