The Conundrum of Three Point Estimation and PERT

Is an estimate based on multiple points more accurate than a single estimate?

If we go with conventional wisdom then it certainly would seem so. A mean of more than one estimate is likely to give us better result.

In project management, there is a three-point estimation technique. It calculates the expected duration based on three different estimates. It calculates the mean of three different estimates to determine the final estimate. This technique can also be used for estimating cost and resources.