Lines of Code Breakdown: A Compositional Analysis

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

Last updated October 20, 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 149,908 commits in 55 open source repos between July 21, 2020 and October 20, 2020. On desktop, hover on a funnel step to get more details about it.

First step: All changed code lines

10,158,496 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

6,915,795 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 3,242,701 lines

Effecting

5,882,723 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 1,033,072 lines

Substantive

4,336,996 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 1,545,727 lines

Purposeful

620,766 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 3,716,230 lines

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Result

6.1% 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. 620,766 (6.1%) impacting lines remain