This is interesting, though I expect it's an upper bound on Copilot productivity boosts:
In my experience it's best at extending things, because it can predict from the context of the file you're working in. If I try to generate code from scratch, it goes off in weird directions I don't actually want pretty quickly, and I constantly have to course-correct with comments.
Honestly I think the whole "build from ground up"/"extending, modifying, and fixing" dichotomy here is a little confused though. What scale are we even talking?
A big part of Copilot's efficiency gains come from very small-scale suggestions, like filling out the rest of a for loop statement. It can generally immediately guess what you want to iterate over. I happened to be on a plane without internet access recently, decided to do a bit of coding anyway, needed to write a for loop, and then was seriously off-put by the fact that I couldn't write the whole thing by just pressing "Tab". I had to actually think about how a stupid for loop is written! What a waste of time!
Honestly I think the whole "build from ground up"/"extending, modifying, and fixing" dichotomy here is a little confused though. What scale are we even talking?
I meant to capture something like "lines of code added/modified per labour time spent", and to suggest that Copilot would reap more benefits the higher that number is (all else equal).
This is in line with my experience. However, the fact that this was an http server is important - I get far more value from copilot on JS http servers than other programs, and http servers are a class that has many no code options - how long would it take them if they were allowed to use pure SQL or a no-code solution?
My opinion: Because of the usual reasons (publication bias, replication crisis, the task being "easy," etc.) I don't think we should take this particularly seriously until much more independent experiments have been run. However, it's worth knowing about at least.
Related: https://ai.googleblog.com/2022/07/ml-enhanced-code-completion-improves.html