A Year-Long Alt Text A/B Test


Alternative text is vital in digital marketing. It makes visual content accessible for individuals who use an assistive device or program to access and navigate through digital spaces.

Alt text also notably impacts Search Engine Optimization (SEO) when applied to images on websites, making it more likely that online users find and engage with your content. However, there is little to no concrete data to support whether or not alt text impacts the engagement of images on social media platforms like Facebook, Twitter, Instagram, and LinkedIn.

Content creators have experimented with keywords in the alt text field on Instagram with varied results. Most have noticed that keywords in the alt text field can affect the searchability of a post within the Instagram app. It was decided to conduct a year-long A/B test that analyzed how alt text possibly impacted the engagement of posts on Twitter, if at all. The test will run from June 1st, 2021 until June 1st, 2022.


Every day at 10:00 a.m. ET, two tweets will post from Alexa's personal Sprout Social account. They will be seemingly identical with the exception of two things. One tweet will have alt text attached to its image and one will not. The other difference is that one tweet will end with a black circle emoji and the other will end with a white circle emoji. Because Twitter does not allow identical tweets to be posted at the exact same time, the emoji are necessary.


In order to eliminate as many variables as possible, which tweet gets scheduled to post first is alternated in Sprout Social every month. Which tweet gets the black circle emoji and which gets the white circle emoji is also alternated.

The only variables that can't be accounted for with the organic A/B test are people knowingly skewing the test when they figure out which tweet has alt text and which does not. It also cannot be accounted for if users have their timelines set to show them tweets in chronological order or by what Twitter’s algorithm recommends to them. To offset this, one random set is boosted in the A/B test each month to get paid data in addition to organic data.

Frequently Asked Questions

Will the results of this test be shared?
How should users engage with the A/B posts?
Is there a way to mute the posts if we don't want to see them?
Where do the images for the test come from?
Will this test be conducted on any other platforms?
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