Susan Ohanian has written one of the best pieces I have seen about Accelerated Reader and Lexile and the rest of the charlatan companies who are purporting to "level" text. Read it here: http://susanohanian.org/show_research.php?id=553. It is comprehensive and detailed and one we should have on hand. Bear in mind that Renaissance Learning has grown into a huge corporate entity. Now Google has invented in it as well: http://mobile.edweek.org/c.jsp?DISPATCHED=true&cid=25983841&item=http%3A%2F%2Fblogs.edweek.org%2Fedweek%2Fon_innovation%2F2014%2F03%2Fwhat_does_the_google_investment_in_renaissance_learning_mean.html. And here is an interesting blog about AR: http://gatheringbooks.wordpress.com/2013/10/12/does-the-accelerated-reader-program-help-develop-lifelong-readers/.
I did a short piece about exiles and levels at the LSU conference as I was talking about CCSS and Best Practices (our best practices, not CCSS practices). I wanted to be sure the audience (combination of librarians, preservice and early career teachers, academics) knew the shortcomings of using formulae of any kind. The participants wee astonished at the handful of slides where I asked them to guess higher lexiles/levels. They got every single one of them wrong. I did not set them up using the most egregious examples I could. I used award winning titles from the past several Newbery and Printz awards to show them the fallacy of science measuring art.
And that is the bottom line, is it not? Measuring art is simply not to be done. Art includes factors that cannot be programmed into a formula, cannot be designed into an algorithm, cannot be boiled down to pixels, syllables, etc. So, let us please call for a halt to this type of measurement with the same ferocity we ask for a halt to the measurement of kids by standardized testing. When we can boil down things, we are often left with little more than soup.