[JackMorgan]

You hit on a key concept that we have no way to even measure productivity. We have no units of measure. What is a feature, they are rarely even comparable in any meaningful way. It's possible to have two projects that start the same but rapidly drift apart.

Not only that but different tools have different depreciation rates. I'd much rather try to restart an abandoned Java or C# project vs an abandoned PHP project, even though the PHP project might have been faster to add features at the start.

Because we have no measurements, we have no science.

[rileymat2]

You can make user metrics/surveys/delivery dates the ultimate adjudicator, in a blind way if you have created complete products. They will diverge significantly!