German codetermination improved labor productivity (value-added per employee) by 16 - 21%.

"Does the additional capital reflect only unproductive amenities demanded by workers (such as nice break rooms) rather than directly productive capital inputs (such as machines)? Our analysis of productivity suggests that this is not the case: we find that shared governance increases labor productivity, as indicated by a 16 to 21% increase in value added per employee, and detect no effects on total factor productivity."