The key word in that last sentence is "comparatively." Where this process falls down for gifted early readers is that the reading level becomes "shockingly" or "insultingly" easy given their ability levels. If the reading is far below their level, you lose their interest, and they miss out on those tiny details that they're asked to regurgitate in order to demonstrate what they term, at that level, "comprehension."
Or they totally shut down any attempts to teach from too-easy material.
Even now, my DS2.7 is brilliantly noncompliant (and quite understandably so!) if someone patronizes him with text like, "A fat fox sat next to a dog on the red mat." It might be roughly the appropriate decoding level for him, but he
despises the lack of meaningful content and will openly mock whoever is "testing" him (ahem...MIL!) or just stare blankly into space. The person might then revert to testing him on phonics and letter names, thinking he didn't know how to read, which would send him running around the room making up jibberish sounds in contempt. Add to that the fact that he often mouths or whispers his reading and it creates a situation where not identifying his ability is highly likely. I imagine older kids might also go underground when unchallenged, or portray a much lower mastery than their actual ability if they are even somewhat perfectionistic.
To a person testing DS who doesn't know him, he'd look like a kid who hasn't even grasped the alphabet, but if they just gave him something at a similar level to the text above, but with more meaning like, "Mad banners, bad manners", he'd read it and then dissect the joke.
