FAQ: 'The Science of Reading' online chatter suggests there are no longer grounds for using levelled text in guided reading lessons for students who are fluent decoders. What are your thoughts?'

This argument seems to be based on the research saying that a lack of knowledge is a key contributor (maybe the key contributor) to comprehension difficulties.
"Using instructional time to get students to read at an instructional level (text levelled at 95% accuracy and 75% comprehension) does not help to develop reading skills as there is no real challenge," they say. "Students need to be exposed to rich content and vocabulary which adds to their general and domain knowledge."

 Of course there is truth there if that is your view of instructional reading.

 But there is also a fish hook. Take the following passage...

Predictions of quantum mechanics have been verified experimentally to a very high degree of accuracy. Thus, the current logic of correspondence principle between classical and quantum mechanics is that all objects obey laws of quantum mechanics, and classical mechanics is just a quantum mechanics of large systems (or a statistical quantum mechanics of a large collection of particles). Laws of classical mechanics thus follow from laws of quantum mechanics at the limit of large systems or large quantum numbers.

Lots of wonderful comprehension challenges for me. But because I have no domain knowledge about quantum physics, my teacher is going to have to scaffold me through the difficult vocabulary and concepts to arrive at a meaningful understanding of the passage. That's going to mean lots and lots of teacher talk.

And that's fine..but let's call that a science lesson and not reading instruction.

 Reading instruction should NOT be about building my students' content knowledge. That may be a welcome by-product but my primary goal should be helping my readers to become increasingly strategic with the skills and strategies of text comprehension (as per Scarborough's Rope).

What 'The Science of Reading' does tell me about comprehension acquisition (Daniel T Willingham "The Reading Mind") is that my ability to comprehend written sentences piggybacks off my ability to understand spoken sentences which of course has been developing since birth.

 When I am confronted by the sentence 'The boy rode his bike along the street' I can attribute meaning to the words 'boy', 'bike,' 'rode', 'along' and 'street' and my knowledge of syntax allows me to understand the sentence. If the sentence is written 'Road the the bike his rode along' ....not so much.'

 And if the next sentence is 'He crashed into a parked car', I can carry the information I have gained from the first sentence to build a storyline. 

 This is what the brain does as it constructs meaning. Much of that initial skill set (basic word meanings and simple syntax) is gained intuitively and is way beyond what we could systematically teach. I am blown away by the understanding of language that my pre-school grandchildren acquire without any instruction.

 So if that is the mechanism of comprehension, what I should be doing is provide opportunities for my students to become 'increasingly strategic' with that process, not sitting around endlessly discussing content. 

I can do some explicit teaching (not too much) about syntax, sentence structure, using context to attack unfamiliar vocabulary, making casual connections within a sentence and across sentences, and making inferences to connect the dots (the bits that the author intentionally leaves out).

 And then I can provide my students with opportunities to have a go at unpacking sentences and observe, observe, observe how they are going with applying this knowledge. Well at least that is what we do in SharpReading guided reading lessons.

 And that is where levelled text comes in.

 I know that if I set the comprehension challenge too high (the combination of vocabulary, syntax and sentence structure) I generate frustration and have to resort to lots of teacher talk. And when that happens, we all know who ends up doing the work.

 My own levelled text, StoryBytes and InfoBytes, allow me to slide up and down the levels, modifying the challenge. I have an open window into how they are processing information and I can then give feedback to tweak their approach.

Here is an example of the different challenges that different levels provide.

Text at a RA 7-8 year Level
"The boy rode his bike down the street."

There are three ideas or concepts that have to extracted and connected to understand exactly what is going on in the sentence. 

The subject is a boy (not a girl). He is riding a bicycle (he is on it) and it is his bicycle, and he is going down a street - that provides the context - probably in a town not a mountain bike trail. 

That same sentence at a 10-11 year Level becomes
"The boy rode his bike recklessly down the narrow street."  

As well as the previous three ideas, the reader has to negotiate 'recklessly' and 'narrow' which add another layer of meaning to the original ideas.

At a RA 14+ year Level the sentence becomes...
"The angry adolescent hurtled down the street on his ape hanger bike with no regard for his own or anyone else’s safety."
What is an adolescent and why is he angry? Are adolescents always angry? What does 'hurtled' tell me? I don't know what an ape hanger bike is but my knowledge of sentence structure tells me it's describing the bike, a type of bike, and there are some clues in 'ape-hanger', and then there is the complexity of the final piece of information, 'with no regard'...so now we have some intent on the behalf of the rider.

Sorry, I am not convinced that there is NO place for levelled text.