Melanie, that’s exactly what I mean; showing stakeholders that the content is too complex for the average user to understand.
The first question is, what does the average user understand? There is an oft-cited statistic that the average adult in the U.S. reads at or below an 8th-grade level. (The study that’s usually cited as the source, the National Adult Literacy Survey, never actually specifies a grade level. It states that nearly half of adults have literacy skills in the lowest two (out of 5) levels, meaning they have inadequate skills for coping with everyday tasks. But I digress.)
If your organization has already specified a target reading level for it’s audience, use that.
So the conversation might go something like this: “I’ve run some samples of this text through a readability formula, and it’s estimating that you’d need a 16th-grade education to understand it. That’s much higher than the 8th-grade reading level of the average adult. Maybe we should test this text with our users to see whether it really is a problem.”