When it comes to progress, there are only two points where we can objectively (well, with high enough confidence) know where we are - 0% and 100%. Anything in between is just guesswork. And people have made very elaborate guesswork tools and systems over the years. Big tools, great methods. But none of that has taken away the fundamental problem - it’s still just guesswork.

The problem with most guesswork is that it’s based only on what we know or can think of. The most significant risks are typically the ones that catch us by surprise. So while some amount of guessing is useful, going too far is sometimes even dangerous (but at least usually futile and waste of time). And trust me, I’ve done my share of those guessworks :). I used to love MS Project.

But, since we can only know 0% and 100%, we should focus on our attention to those numbers. 0% is easy - we haven’t done anything yet. But in waterfall, we start everything (with requirements) very early. We invest some into everything, then invest some more (planning), and invest even more (desing, then coding), before getting to the point where we can evaluate whether it all works or makes sense to our customers. So if we want to know as much of 0% as possible, we should not any work on most of the stuff.