Given the difficulty of estimating the duration of project activities, many project managers believe "only after the fact do we know which path was the actual critical path?"a. Do you agree?b. Based...

Given the difficulty of estimating the duration of project activities,

many project managers believe "only after the fact do we know which path was the actual critical path?"a. Do you agree?b. Based on your experience what are some of the approaches (quantitative or qualitative) that can be most useful in estimating activity duration?