The Hidden Cost of Slow Code Reviews: Data from 8 Million PRs

How review bottlenecks drain engineering productivity — data from LinearB, Google, DORA, SmartBear, and Meta. Your pull request has been open for two days. You've context-switched three times, started a new feature, and honestly forgotten half of what you wrote. When your teammate finally reviews it, you'll spend 20 minutes just re-loading the context. This isn't a one-off bad week. This is the default. LinearB analyzed 8.1 million pull requests across 4,800 engineering teams and found that half of all PRs sit idle for over 50% of their lifespan. A third of PRs? Idle for nearly 78% of the time between creation and merge. Not being worked on. Not being reviewed. Just... sitting there. I spent a few weeks pulling together data from LinearB, Google's engineering research, DORA, SmartBear, and a handful of academic studies. Here's what I found about what slow code reviews actually cost — and what the best teams do differently. The numbers LinearB's benchmarks break teams into tiers based o