Lets say you’re planning a trip across the UNited States, starting in Washington state and going all the way to Florida. Your only tools for the trip are a car and a crude map that you created based upon your previous travels. Most of your navigation will come from reading highway signs and you have no way of anticipating construction, accidents, or detours.

So you’re planning this trip and I ask you how long the trip will take. How accurate do you think your number will be? Do you think you’d be off my minutes or hours?

Now imagine your getting close to the end of your road trip but you’re way behind schedule because you ran into multiple detours. And then someone tells you that you should get someone else to help with the driving so you can keep moving through the night rather than stopping to sleep.

But this new person doesn’t know how to read the map you’ve created. You didn’t think about it needing to be for anyone but yourself. So this new person doesn’t know exactly where you’re going. And this new person also doesn’t know how to drive your car. I don’t know why she doesn’t but she just doesn’t, although she is familiar with the concept.

So the first few hours of driving together are at a slower pace than you were at because you’re spending some time teaching her how to drive the car. And she can’t drive at night yet because she doesn’t know the way well enough so you aren’t seeing the amount of extra progress you expected. It isn’t long before you’ve realized that she’s not a help and only slowing you down. It isn’t that she’s done something wrong it’s just that she can’t learn what she needs to learn fast enough to make a difference in your drive.

This situation I’ve described is very similar to software development projects. We don’t have tools to tell us the effect route to avoid trouble and we only have our own experience and ingenuity as a guide. But one anticipated detour in code can easily add hours or days to a project and there is no way to avoid that. The transfer of information between a team is one of the biggest hurdles that needs to be overcome and unfortunately adding a person near the end can only cause harm. But there is one difference between the two scenarios – the time scale. A minute in this road trip is the equivalent of an hour or more.