When shown that there's no solid evidence for their side, literacy gurus demand evidence for the other

Over the past month or so, Tim Shanahan and I have been having an interesting discussion in the comments section to one of his blog posts.  I've been pleased that he's taking the time to respond thoughtfully, but he's not convincing me.  I'm writing this post, even more than some others, to clarify my own thinking--apologies for getting too much into the boring weeds here.

Initially I asked for evidence that reading more informational text led to better comprehension of such text. He said there was lots of evidence, I asked for specifics, and he finally admitted, after a few back-and-forths, that "You are correct that there is no study showing that increasing the amount of the reading of informational text has had a clear positive unambiguous impact on reading achievement or student knowledge. "

Shanahan did not, however, address why he had written in his blog post:CCSS is emphasizing the reading of literary and informational text to ensure that students are proficient with a wide variety of text. Nor did he address why, when I asked for evidence that reading more information text led to greater proficiency with informational text, he responded by saying "Actually there is quite a bit of research showing that if you want students to be able to read expository text, you have to have them read (or write) expository text."

Instead of explaining why he had made incorrect statements about the evidence for reading informational text, Shanahan asked me to show the evidence for reading literary text.  He doesn't seem to get it: my whole point is that there is not strong evidence either way, and it is dishonest to pretend that there is.  He, and many other scholars who engage in education discourse aimed at teachers and the general public, are continually pretending that there is strong scientific evidence for their pet curriculum ideas. Very often there is no such evidence.

When I suggested that a lot of "evidence-based" educational policies are not founded on particularly strong evidence, Shanahan made an interesting move: he essentially said that I was demanding too much.  As he put it, "the basic problem here is with your understanding of research and how causal claims are put forward." He said that what he and others do is to look at some available evidence and come up with a "logic model" that fits the facts.  Not all research is done, because some questions, like " Is third grade really necessary?", are not going to be studied.

So he seems to think if you have a story that is not inconsistent with some emprirically established facts, then apparently you have the right to say that "there is quite a bit of research showing" that your story is true.

Maybe.  But it seems to me that if there is debate about a question, like the question of whether it is worthwhile to make young children read more informational text, then if you say there is "quite a bit of research showing" that your side of the debate is true, you have to have evidence that is not only consistent with your side of the debate but also inconsistent with the other side.

And it's not like we couldn't do some studies!  Nell Duke, a prominent proponent of more informational text in the early grades, has gotten millions of dollars in grant money and has spent over a decade studying the issue of how much informational text children "are exposed to" in school.  Couldn't she have taken some of that large amount of time and money and done a controlled experiment?  Surely some district would have been happy to have a huge library of informational text provided to half of their K-4 schools, so that Duke could check whether students at those schools would actually do better, a few years down the line, at understanding informational texts?  But she didn't do it, and Shanahan didn't do it, and now Shanahan is implicitly suggesting that such research would be as silly as a controlled experiment in which we got rid of third grade.

I'm still trying to figure out what I think about "research-based" arguments.  I guess my position now is: research can be useful and informative, but it is only rarely, to use a legal term that has been cropping up a lot lately, dispositive; and we should have a lot more of it before we take the kind of authoritative tone that Tim Shanahan and a lot of educational experts take when they are writing for a popular audience.  In their scholarly papers, and when pressed in debate, these experts are circumspect and honest about the limitations of their certainty; I'd like to see more of that circumspection in the advice given to us teachers and to the public.