If you have ever watched people playing on the tennis courts, you see two, or four, players in a game, actively running around and hitting a ball back and forth. Many rackets, one ball in the game.

Have you ever taken a look at the edge of the court? There are tennis balls, lots of them, scattered around in little clusters all around the outer edge. All through the game, when someone misses a ball or serves one out of bounds, sometimes the ball ends up so far away that the players just go get another one from their bags. Before you know it, everyone has lost count of how many balls have rolled off.

That’s what it’s like at a software company, too. Only the players are developers, and the balls are requirements. In the heat of the game, with deadlines looming and tasks to complete, requirements get cut, skipped, or forgotten. They roll off the playing field.

And the person who is best positioned to notice those many requirements that have been left for another day is the Product Manager. If you ever wanted a snappy and memorable definition of a Product Manager, it’s this: “The Product Manager is the person who makes sure that the requirements don’t get lost or forgotten.”

Read on for a discussion of how Product Managers can play a vital role as the Requirements Police, making sure that important requirements are not forgotten.