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🎓 Shareable Code Research

The prospect of using data and measurement to inform engineering goals is a novel idea for many teams. For those considering whether to champion code review, measurement, and data in general, here are a few PDFs to help spark a conversation with your team.

Diff Delta™ correlation research
Academically-reviewed research on the correlation between Diff Delta and developer effort, suggesting improvement vs. Commit Count
Diff Delta™ benchmark research
Data to help gauge whether development efforts are approaching product/market fit
How Commit Groups enhance Diff Delta™
Learn how Commit Groups create a historical tapestry that picks out substantive changes from noise

Diff Delta™: It's Not Magic, It's Math

While it's true that Diff Delta™ incorporates an unprecedented number of factors to assess the volume of durable code change occurring, each factor is based in empirically-derived first-principles.

The funnel below visually illustrates how the Diff Delta algorithm detects the kernel of "meaningful change" from among millions of raw code changes that are processed every day. It does so by filtering out the few percent of changed lines that have proven to correlate with developer effort.

All line counts are extracted from real world code changes across 723,483 commits in 109 open source repos from Microsoft, Google, and Meta between June 22, 2025 and September 21, 2025.

First step: All changed code lines

46,860,604 changed lines of code factored into analysis

All changed code lines

The total lines of code in our most recent data set. This includes all lines that changed in any commit, so it is equivalent to the "Lines of Code" metric provided by GitHub or Pluralsight Flow. Removes more lines

Distinct commits

23,076,992 lines remain

Distinct: Ignore duplicated fragments

This step rinses all lines of code that occurred in a branch that is discarded, or code that is committed in multiple branches or sub-repos, forked repos, . Removes 23,783,612 lines

Effecting

18,340,533 lines remain

Effecting: Remove semantic lines

Changes that modify white space, blank lines, language keywords (e.g., begin, include), or types of lines that don't contain meaningful code content relative to the file type. Removes 4,736,459 lines

Substantive

13,825,574 lines remain

Substantive: Negate batch operations

Diff Delta approximates cognitive load per commit. Operations like move, cut/paste and find/replace change many lines but do not represent high cognitive load, so are discarded by this step. Removes 4,514,959 lines

Purposeful

1,459,894 lines remain

Purposeful: Rinse commit artifacts

To normalize away the difference between a developer who commits 100 times vs 1 time daily, we identify churned code, and we devalue large-scale additions (like new libraries). Removes 12,365,680 lines

💎
Result

3.1% of total
1,460k final LoC

Important code line changes

Once you've cut through all the layers of noise that cloud lines of code, you find only a fraction of code evolving its repo in a purposeful, substantive way. 1,459,894 (3.1%) impacting lines remain

A Visual Guide to Diff Delta™ and Commit Groups

Our downloadable PDF is the most sharable way to introduce your team to how Diff Delta and Commit Groups. We'll show how these two work together to drive better results for your team. In this guide, you'll learn:

  • How your current git provider compares to GitClear
  • Why hundreds of teams trust GitClear to make better decisions
  • How we identify bugs & tech debt overlooked in your current process

Imagine: all of this and more in less than 3mb :-)


Download the Visual Guide to Diff Delta and Commit Groups

Diff Delta™ Distribution

The tables below illustrate the range of weekly Diff Delta values accumulated per developer. All percentiles are recalculated daily.

Read more research exploring how user interest & business revenue grows alongside Diff Delta.

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