The impact of hardworking employees on their less diligent colleagues
Slate
investigates the question
"Do hardworking employees make their slacker colleagues more productive?"
Tim Harford cites
the study
Peers at Work by Alexandre Mas and Enrico Moretti
which used a grocery store check-out line as its laboratory,
and the results are illuminating.
(It may be hard to find, but the key paragraph is in the middle
of page 4, the one that begins, "We find that...")