### Problem to solve Mean Time To Merge (MTTM, also referred to as Average Time To Merge) is widely used as a measure of devops health in the software development industry. In fact, GitLab itself uses MTTM as one of its [primary development KPIs](https://about.gitlab.com/handbook/engineering/development/performance-indicators/#mean-time-to-merge-mttm), and is [auditing](https://gitlab.com/gitlab-com/www-gitlab-com/issues/6273). It seems there is clear demand for a GitLab interface that would help users understand MTTM. ### Intended users * [Parker (Product Manager)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#parker-product-manager) * [Delaney (Development Team Lead)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#delaney-development-team-lead) * [Sasha (Software Developer)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#sasha-software-developer) ### Further details Validity: MTTM is not a sophisticated measure. Values are relative, and both low and high values can indicate dysfunction. However, enough data can help establish a representative average that can be used as a reference point. Some questions an MTTM interface could help answer: * Is code review time rising, falling, or stable over time? (for identifying good or bad trends, or understanding the impact of changes) * Where is code review time highest? (for identifying complex code and dysfunctional reviews) * Where is code review time lowest? (for identifying best practices or insufficient reviews) ### Proposal Add a group-level "MTTM Analytics" page, accessible from the left-nav, that displays a "MTTM" chart with 2 lines: 1. The average time for merge requests to be merged, grouped by month for the past 12 months, for merge requests meeting these criteria: 1. Targeting `master` 1. The average across the available data (horizontal line) The data displayed in the chart can be specified using the filter bar. ### Proof of concept See [throughput_by_month.rb](https://gitlab.com/gitlab-org/gitlab/-/issues/229047#proof-of-concept), which also generates MTTM data.