McKinsey clain, they can measure developer productivity[1]
McKinsey is a company that has no idea what the business they are supposed to be advising actually does.
Usually (actually always) a company is worse off afterwards and many people are unemployed.
I bet that companies that listen to such promises will soon have significant security problems in the software, and the code will become very poor in quality.
A German cabaret artist coined the phrase: Consultants are eunuchs - they know how to do it.
[1]
McKinsey: Yes, you can measure software developer productivity