I'm using a maximum a posteriori probability (MAP) estimator in a classification problem. After estimating all the a posteriori probability, the standard way is to simply take the class associated with the maximum probability. I would like to measure the confidence of this decision. I.e. if the maximum a posteriori probability is not significantly larger than the rest, I would like to skip the case (which would reduce recall but increase precision).
Is there a standard way to measure such concept?