Not all spam is created equal, it turns out: A recently published academic study, which analyzed more than 300,000 political emails sent during the 2020 election, found evidence of a political bias in how the nation’s most popular email inbox providers filter messages. Google’s Gmail was 50% more likely to designate emails from Republicans as spam than messages from Democrats. And on the flip side, both Microsoft Outlook and Yahoo were significantly more likely to filter out messages from Democrats than from Republicans.
Error-prone filtering from the most popular email service in the country may have a major impact on elections in the United States. Online fundraising relies primarily on email solicitations, and the Republican National Committee estimates it may have lost up to $2 billion in contributions since 2019 because fundraising messages were sent to spam filters. Beyond fundraising, campaigns are also hampered in their ability to combat disinformation, share accurate information about voting and encourage supporters to go to the polls.
Google said that correlation is not evidence of causation and that “political affiliation has absolutely no bearing on mail classifications in Gmail.” Microsoft likewise chalks the discrepancy up to technology that isn’t perfect.
Sorting algorithms are notoriously a black box, and in this case for some good reasons — if any rules were made public, they would be immediately circumvented. But because these companies do not make their spam filtering algorithms available for scrutiny, we cannot know for certain whether or not some political factors — intentionally or otherwise — contribute to an email’s classification. But we can agree that if a voter opts in to receive email messages from a political candidate or party, they should be able to receive them.