Here’s some links about programmer productivity as time breakdowns for developers. This is something I had to put together for work. Basically, the concept is that it takes longer to read a program than to write code. I think this is especially true in maintenance programming. You can spend lots of time finding the problem, a small amount of time fixing it, a large amount of time testing. So write good code, people!! Make it easy for the next developer to work on your programs.
Photo credit: Grafixar from morguefile.com
This link has some references to studies:
One comment that I have is that not all programming tasks are the same and not all programmers operate at the same level. Here is something that is not a study but makes the point. http://www.devtopics.com/programmer-productivity-the-tenfinity-factor/
Someone can produce tons of code but that doesn’t factor in how useful the software is and how bug-free it is.