Extreme Programming Installed

Spike Solution

It really is easy to estimate the difficulty of stories compared to other stories. Brainstorm what the tasks are a bit, then see what you've already done that is about that size, or twice the size, or half, or one and a half, as we described above.

But what if you haven't done anything like this story before? What if it's the beginning of the project and you haven't done anything at all?

The answer is simple: do some experimenting. We call such an experiment a spike solution, to remind us that the idea is just to drive through the entire problem in one blow, not to craft the perfect solution first time out. You need to know how long it will take to do something. To know that, you need to know how you'll go about it, but you don't ...