alt Hacker NewsDevelopers don't like being measured for good and bad reasons. The good reason is that there is lots of effort that we expend that isn't always captured in metrics like long pieces of design or training others etc. The bad is that we don't being told that we aren't as productive as other people even if we are!
My experience is that these are only useful over a long enough period and across enough people that we can spot genuine outliers. For example, your average across the last 6 months is "15" and the average of everyone else is "25", can you help me see whether you are being given too much off-target work or are there any other issues that are blocking you getting stuff done?
Also trying to reduce productivity to some thing as silly as pull requests per hour etc ignores valuable contributions else where. Design, push back, quality, mentoring, leadership. I thought that is why meta had the "coding machine archetype" and other archetypes, recognising that just PRs aren't the only measurements.