I’m confused. It kinda sounds you are asking what metric needs to have a bias for it in a study. If you otherwise have information that you believe would demonstrate the point, just share that.
I'm asking for any material that supports this statement: "businesses realise that regular time off (and as much time as you need if ill) increases happiness and therefore productivity."
Productivity can be measured and if that productivity was increased then those statistics should be more visible!
Productivity can be measured and if that productivity was increased then those statistics should be more visible!
I would love to have a 4-day work week.