Working harder (if overtime is uncompensated) does increase productivity. But it’s an abusive and ineffective or even counterproductive practice. I used to lead a service line within a medium-sized consulting firm, and I made it clear to managers reporting to me that forcing their staff into extended overtime in order to meet milestones would get those managers sacked for bad planning. It only took a couple firings before the other managers started taking it seriously. The biggest problem was managers bidding jobs with the clients that assumed the whole squad would be working 60-70 hours weekly. That’s burning out our people to take on work which, if correctly estimated, wouldn’t be profitable for the firm. And that leaves zero contingency for when something goes wrong, which it often does.

But the moronic frat boys who run many IT firms and consultancies still try that One Simple Trick, on the assumption that if they burn out their staff, there are always more suckers who can be found to replace them.