When managing projects that are funded by other people's money, we are obligated to know something about the probabilistic outcomes of our work. Without the ability to make forecasts and estimates of these outcomes , we are relegated to the category of labor.
As Project Managers, we must learn to estimate and forecast to some level of confidence. This is not guessing, that is child's play. Choosing not to estimate is also child's play. We must learn to make estimates based in sound statistical and probabilistic principles. Without that, the very notion of Return on Investment is intentionally ignored.
Return on Investment = (Value produced - Cost to Produce) / (Cost to Produce)
It's that simple and it's that hard. The cost and value variables are probabilistic estimates and must be treated in that way. But without knowing either of these, to some degree of confidence, we cannot make informed management decisions.
That is the primary role of project management or engineering development -
Make Decisions based on evidence in the presence of uncertainty
