[ravenstine]

While we're at it, let's measure productivity by lines of code added. /s

Using merge time is a terrible metric, perhaps worse so than deadlines because it can be more effectively weaponized. What would the incentive be for the developers other than to rush the code review process? Merges are not where you want to be rushing anything, but rather the opposite. If project deadlines are necessary, allowing code review its due time affords developers the ability to informally schedule things without sacrificing craftsmanship for what in reality is a vanity metric. Some code needs the be carefully considered and given time while other code doesn't necessarily need much review or worry at all, but no one can tell that by looking at mean time. If a developer is asked why some tasks had a longer than average mean time, then now they have to waste even more time by explaining themselves. In the worst case, the incentive to rush the review process results in more time wasted on bugs that could have been caught before they even had a chance to be merged.

Am I misunderstanding your view of how mean time to merge would be used?