TL;DR

• 46% of all merged PRs were stamped by reviewers without any top-level or inline comments
• 19% of all merged PRs have fewer than 3 words across all reviews that PR has received — the most common text being a variation of “LGTM,” a thumbs up emoji, or “thank you.”
• We therefore propose that 65% of merged PRs are approved with minimal comments

46% of all merged PRs were stamped by reviewers without any top-level or inline comments

• Interestingly, 8.4% of all merged PRs were stamped by multiple reviewers, all of whom did not leave any inline or top-level comments.
• Methodology:
  • We limited PRs to those merged by active committers from 1/2023 to now. (If we don’t limit to active developers, then 49% of merged PRs are stamped without any comments.)
  • To calculate the prevalence of PRs that were merged after blind approvals, we first aggregated all reviews and comments a PR has received — and filtered for PRs without any reviews, comments, or change requests.

52% of all merged PRs were approved with text in the top-level review or in-line comment.

• 52% of all merged PRs were (eventually) approved with either text in a review or after some back-and-forth with changes requested
  • 16% of all merged PRs had both some distinct other activity (comments or change requests), alongside a no-comment stamp — perhaps after comments were addressed.
  • 36% of all merged PRs were directly approved with some text in the review
• Of the 36% of the merged PRs that were directly approved with some text in the review:
  • 19% of total merged PRs have fewer than 3 words in the review after combining all reviews a PR has received (52% of the 36%)

• Further breaking down the PRs approved with some text, the most popular responses include:
  • LGTM and various variations of LGTM (e.g., LGTM thanks; looks good)
  • Emojis (mostly 👍) are the second most popular
  • Followed by “thank you” and variations

65% of PRs merged are merged after what seems to be a “quick stamp”

• We categorize a quick stamp as, across all reviews received by the PR, there were 0-3 words in the review text.