The most interesting thing about this study for me is that when they break it down by experience levels, developers who are above the median tenure show no stat

The most interesting thing about this study for me is that when they break it down by experience levels, developers who are above the median tenure show no statistically significant increase in 'productivity' (for some bad proxies of productivity), with the 95% confidence intervals actually dipping deep into the negatives on all metrics (though leaning slightly positive). This tracks with my own experience: Copilot is nice for resolving some tedium and freeing up my brain to focus more on deeper questions, but it's not as world-altering as junior devs describe it as. It's also frequently subtly wrong in ways that a newer dev wouldn't catch, which requires me to stop and tweak most things it generates in a way that a less experienced dev probably wouldn't know to. A few years into it I now have a pretty good sense for when to use Copilot and when not to—so I think it's probably a net positive for me now—but it certainly wasn't always that way. I also wonder if the possibly-decreased 'productivity' for more senior devs stems in part from the increase in 'productivity' from the juniors in the company. If the junior devs are producing more PRs that have more mistakes and take longer to review, this would potentially slow down seniors, reducing their own productivity gains proportionally.