I think those numbers are probably based on source code contributions. I can believe those statistics, what is missing is the why.
Some people just aren’t good programmers. I knew some of those, one turned out to be great at testing instead. Junior programmers, new programmers (to the project/company or language or field) are slow and they might get better. Then you have burnout. There was a story here about a guy that didn’t contribute much because he mentored and pair programmed and did other tasks to make the life of other programmers easy.
There are a lot of good reasons so before you go optimizing on numbers, check the why.
Some people just aren’t good programmers. I knew some of those, one turned out to be great at testing instead. Junior programmers, new programmers (to the project/company or language or field) are slow and they might get better. Then you have burnout. There was a story here about a guy that didn’t contribute much because he mentored and pair programmed and did other tasks to make the life of other programmers easy.
There are a lot of good reasons so before you go optimizing on numbers, check the why.