[anuy]

i agree that working with breaks and socializing with colleagues for a coffee/a walk/ a fresh breath of air is good for productivity. however i do not agree with some posters who say that there are no metrics to measure productivity. there are ways to measure programmer productivity. not talking about lines added or features added. in general we can get a sense of how involved is a feature addition by looking at the list of data structures needed, algorithms to process the data, algorithms to list/display the output. more formal methods--http://secse08.cs.ua.edu/Papers/Danis.pdf

[prodigal_erik]

That approach can set a sort of lower bound on how much work a feature requires, but judging productivity also involves measuring how often the program fails to meet its specification and how much work to modify it could have been avoided up front.