"The experiment confirmed what language researchers have long maintained: the key to comprehension is familiarity with the relevant subject."
This Op-ed article from the NY Times, Reading Test Dummies, brings up a great point about our tests and their authenticity. To find content that would be familiar to every student would be tough. However, I think it's important to make it relevant, if it is to be an authentic assessment the test should have a connectedness to the real world they live in. Would it still be a standardized test if the prompts were different? I'm unsure, but like the author said, asking a student to read for comprehension on a topic like "taking a hike in the Appalachians even though they’ve never left the sidewalks of New York, nor studied the Appalachians in school" seems biased and unfair.
Why do we ask kids to engage in, and analyze a reading passage differently than we do as adults?
I think there are other factors, too, like passion for a subject or curiosity; these would impact relevance I think, too.