Demian Entrekin at the IT Toolbox blog cites two problems in product management that, in my marginally humble opinion, are actually the same problem. First, there are the unrealistic schedules:

I have to admit that I have done this myself. I often put down a schedule that I know in advance is not exactly realistic. I call this the internal plan. Then there’s the external plan. That plan is more vague and has something like a 50% pad built into it. Some people call this sand bagging, but I call it managing expectations.

And then there’s "Information Uncertainty":

But from where I sit, Information Uncertainty is quite a different animal. In short, Information Uncertainty means we don’t know what will happen as an idea moves through the life cycle toward becoming a project and then launch. There is a tremendous amount of uncertainty. The idea may lead to substantial change. It may lead to incremental change. It may never make it to funding. It may be a great idea that we simply fail to execute.

Actually, these are both facets of the same problem. It’s called friction, the tendency of plans to unravel as unexpected obstacles appear. If you were a CS major in college, you might not have heard that term. If you’ve ever gone through officer training in the US military, chances are that you have.

Friction, in this paricular sense of the word, comes from a classic work on military strategy, Carl von Clausewitz‘s On War. Military professionals have a lot of anxiety about plans that fall apart, since they usually involve people shooting at you. Therefore, people like Clausewitz, a Prussian veteran of the Napoleonic Wars, have a very strong motivation to understand why plans fail.

Everything is very simple in War, but the simplest thing is difficult. These difficulties accumulate and produce a friction which no man can imagine exactly who has not seen War, Suppose now a traveller, who towards evening expects to accomplish the two stages at the end of his day’s journey, four or five leagues, with post-horses, on the high road–it is nothing. He arrives now at the last station but one, finds no horses, or very bad ones; then a hilly country, bad roads; it is a dark night, and he is glad when, after a great deal of trouble, he reaches the next station, and finds there some miserable accommodation. So in War, through the influence of an infinity of petty circumstances, which cannot properly be described on paper, things disappoint us, and we fall short of the mark.

Given the inevitability of the unexpected, no commander should ever base a strategy on everything going exactly according to plan. As another smart Prussian said, "No plan survives contact with the enemy."

While product development in the technology industry is a lot safer than military service, ignoring the role of friction is just as foolish. Go ahead and be aggressive–just be realistic. If you’re worried about keeping people motivated, just remember that no one is motivated by doing a third rate job, or finding out that the original schedule was a crock.

Hire good people who want to meet deadlines, and assume that even the smartest people can’t anticipate everything that might go wrong. If you ever catch yourself assuming that everything will go right, buy a copy of On War and smack yourself in the head with it.