Program Evaluation and Review Technique (PERT)
Trying to estimate the time to allocate for a specific task can be a troubling undertaking. Many times we have ideas and conditions that can produce several varied estimates, but none of which are perfect. Below is a simple formula to help consider all of those cases.
(Optimistic + 4(Most Likely) + Pessimistic) / 6
By using this formula one can get better but simple measurement of the time required for a task. However, it should be noted that the more complex of a task generating three separate estimates will drive up the time required to complete a time estimate.