Lines of Code Breakdown: A Compositional Analysis

Results of analyzing 10 million lines of code across the largest Open Source projects

Last updated November 27, 2020

There are a lot of tools that provide stats on lines of code (LoC). Conventional wisdom has long held that these metrics are fraught, but absent hard data, it has only been possible to gesture toward the disadvantages of relying on LoC, without statistical proof.

GitClear has previously asserted that only 5% of lines of code meaningfully evolve the repo's code base. Because it is an extraordinary claim that 95% of LoC is noise, it is beholden upon us to substantiate this claim with data. That is the purpose of this page.

The funnel below aggregates real world lines of code measurement across 150,754 commits in 58 open source repos between August 28, 2020 and November 27, 2020. On desktop, hover on a funnel step to get more details about it.

First step: All changed code lines

10,763,910 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.

Distinct commits

7,335,834 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 repos. Removes 3,428,076 lines

Effecting

6,226,034 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 1,109,800 lines

Substantive

4,573,140 lines remain

Substantive: Negate batch operations

Line Impact approximates cognitive load per commit. Operations like cut/paste and find/replace change many lines but do not represent high cognitive load, so are discarded by this step. Removes 1,652,894 lines

Purposeful

663,627 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 3,909,513 lines

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Result

6.2% of total

Meaningful lines of code

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 meaningful way. 663,627 (6.2%) impacting lines remain