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blog: Don Marti

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Blind code reviews experiment

13 July 2017

In case you missed it, here's a study that made the rounds earlier this year: Gender differences and bias in open source: Pull request acceptance of women versus men:

This paper presents the largest study to date on gender bias, where we compare acceptance rates of contributions from men versus women in an open source software community. Surprisingly, our results show that women's contributions tend to be accepted more often than men's. However, women's acceptance rates are higher only when they are not identifiable as women.

A followup, from Alice Marshall, breaks out the differences between acceptance of "insider" and "outsider" contributions.

For outsiders, women coders who use gender-neutral profiles get their changes accepted 2.8% more of the time than men with gender-neutral profiles, but when their gender is obvious, they get their changes accepted 0.8% less of the time.

We decided to borrow the blind auditions concept from symphony orchestras for the open source experiments program.

The experiment, launching this month, will help reviewers who want to try breaking habits of unconscious bias (whether by gender or insider/outsider status) by concealing the name and email adddress of a code author during a review on Bugzilla. You'll be able to un-hide the information before submitting a review, if you want, in order to add a personal touch, such as welcoming a new contributor.

Built with the WebExtension development work of Tomislav Jovanovic ("zombie" on IRC), and the Bugzilla bugmastering of Emma Humphries. For more info, see the Bugzilla bug discussion.

Data collection

The extension will "cc" one of two special accounts on a bug, to indicate if the review was done partly or fully blind. This lets us measure its impact without having to make back-end changes to Bugzilla.

(Yes, WebExtensions let you experiment with changing a user's experience of a site without changing production web applications or content sites. Bonus link: FilterBubbler.)

Coming soon

A first release is on a.m.o., here: Blind Reviews BMO Experiment, if you want an early look. We'll send out notifications to relevant places when the "last" bugs are fixed and it's ready for daily developer use.