From Outliers by Malcolm Gladwell:
In commercial airlines, captains and first officers split the flying duties equally. But historically, crashes have been far more likely to happen when the captain is in the “flying seat.” At first this seems to make no sense, since the captain is almost always the pilot with the most experience. … Planes are safer when the least experienced pilot is flying, because it means the second pilot isn’t going to be afraid to speak up.
The context of this excerpt is an examination of airplane crashes in which the copilot was aware of the pilot’s errors but did not speak up assertively.
I wonder whether an analogous result holds for pair programming. Do more bugs slip into the code when the more experienced programmer has the keyboard? The German aerospace company DLR thinks so. The company pairs junior and senior programmers. The junior programmer writes all the code while the senior programmer watches.