TL;DR

• The median active developer’s PR is merged 9 hours after publishing. When excluding PRs merged without any reviews, the median developer’s time to merge increases 55%, from 9 to 14 hours.

• The median PR is merged within 3.5 hours after publishing. Excluding PRs without reviews, the median time jumps 71% to 6 hours.

• Here are our main takeaways:

  • As expected, reviews play the largest role in determining a PR’s time to merge.

  • The majority of all PRs merged are from a smaller set of developers who merge more frequently.

  • Developers who merge more frequently also tend to merge faster and merge more often without waiting for reviews.

The median active developer’s PR takes 9 hours from publish to merge.

If we cut by how frequently developers’ weekly merge frequency, we see that developers who ship code more frequent tend to have lower hours-to-merge. (See how we define active developers here)

When we limit to PRs with any reviews, then the median active developer’s PR increases to 14 hours to merge. While we see the time-to-merge increase across the board, reviewing PRs tends to affect more prolific committers.

• Developers who merge a median of ≥ 4 PRs a week see a 42% increase, from 3 hours to 4.4 hours

• Developers who merge a median of 1 PR a week see a 9% increase, from 17.3 to 18.9 hours.

The median PR is merged within 3.5 hours of being published.

• The median PR's time-to-merge is 3.5 hours but, as noted above, a median developer's PR takes 9 hours to merge. The difference can be attributed to PRs that are merged without review and more prolific developers, who merge more PRs and merge them faster

• 37% of PRs are merged in under an hour. Of these < 1 hr to merge PRs, 34% are merged without any reviews.

• There is a very long tail: the average PR is merged 47 hours after being published.

• 3.5 hours is primarily driven by PRs that are merged without any reviews. When we filter for PRs with any reviews, the time to merge jumps to 10 hours. Unsurprisingly, PRs with more reviews prior to merging take longer to merge.

What factors affect a PR’s time to merge?

The single largest factor is that affects a PR’s time to merge is whether it is merged with any reviews. Upon limiting to reviewed PR, factors that most affect time to merge are:

• time to first review
• the number of reviews
• the number of lines modified in the PR
• company size

We will dive more into each topic later.

How we calculate developer median time to merge:

To calculate a median developer's median time to merge, we:

• Filter for active developers and their PRs merged since 1/2023

  • When the analysis calls for it, we further filter PRs (e.g., to only those with reviews)

• Calculate the median time between a PR publish time and merge time per developer

• Calculate the median time to merge across all active developers

  • When called for, we further cut developers by dimensions such as their org size, their median PRs merged per week, etc.