Up until today this has been my understanding. But now, after releasing a specific feature to production, I realize the "beginners" aren't toddlers that need a little help getting the ball down the lane... they are actually 900lb gorillas walking in to my bowling alley, finding the stash of 22 pound bowling balls, facing with their back to the pins, and launching them wildly like the first pitch at the world series.
What's your analogy to software engineering?
This is also why traditional delivery planning fails. "How long is it going to take to build this road?" "Well, we know roughly how long, be we don't yet know the exact route we will take or the obstacles we will encounter, so we'll report on our progress and let you know when we arrive."