Short Iterations

We use a three-week "iteration", into which the project is time-boxed. User stories were broken down into engineering tasks. If an engineering task appears to require more than one engineering week, it must be broken down further.

Engineers estimate their own tasks, in "perfect engineering days". That is, they estimate the time it would take to do the task if everything went perfectly, they weren’t interrupted, and so on. We assume (and it has held up well under measurement) that there are two real days per perfect day. Therefore each engineer signs up for enough tasks to fill 7 or 8 days in each iteration.

On the contrary, since you do pair programming, doesn’t that cancel out the factor of two?

On the contrary, the ratio of 1 to 2 accounts for engineer’s errors in estimating how effective they are. Don’t different engineers have different ratios?

1997, 1998, Ronald E Jeffries