[renesd]

They don't need to back it up. It is up to the person making the original claim to back it up.

There's half a century of research and practice into this topic. Anyone in the industry _should_ know about this. Anyone who doesn't can find it on a search engine within 30 seconds.

[Retric]

No, it's a well known problem. The old lines of code joke still applies. You can introduce metrics, but those will just be gamed because software is a multidimensional optimization problem with complex trade offs. So, you can't translate that to a single measurement and call it productivity.

[renesd]

Yes, it's a well known problem.

[AndrewDucker]

There's half a century of research - and yet, no clear way of measuring productivity, that I am aware of.

If you're aware of one then a link to an article about it, or even a wikipedia page, would be awesome.