That's the title of a campaign from the Engineers (just for a tiny bit of context they're affiliated to the Labour party and are the most right-wing private sector union). Increases in productivity over and above increases in wages is just increasing the amount the bosses get from the workers' labour.
From the press release:
The EPMU will support employers who develop genuine productivity initiatives.Because the union's job is to support employers, but only those who are genuinely trying to get more money out of workers.
The nearest I have come to a Marxist conversion came during a discussion about productivity in the union movement. Marxist economics made so much sense right then (which is strange because 90% of the conversations I've had about Marxist economics have been about the fact that they ignore unpaid labour).
Also posted at Alas