Would a senior and junior programmers' combined productivity be significantly higher if they were paired up instead of working separately?
Assuming, for the sake of discussion, that the senior programmer has 15+ years of experience and the junior has <1 year.
As for the senior programmer's productivity, that depends: if he is currently working near peak efficiency, having a junior programmer in his way will slow him down; if he is having motivational problems (as you implied in the earlier phrasing), having a junior programmer around may help him focus his attention, and achieve more.
I'm wondering how well it would work for the senior programmer to explain a very small, 5-minute task to the junior, then work on something else while the junior guy finishes the task, then check the work, and repeat.
I'm more interested to hear if anyone has ever actually tried this, and if there were any surprises or if it didn't work, why didn't it work?