I (O.P.) want to be clear for the record that I am not endorsing (though not discouraging either) that Engelmann's or DISTAR methods be the new guiding light in schools. I can certainly envision that implementation going awry for lots of reasons.

I'm just stating that this particular book, in a 1:1 parent:child setting, has a great track record. 100 days of spending 10-15 minutes with your kid doing these lessons is a low risk intervention with tremendous upside. You don't have to have a teaching background to utilize it (the intro for parents is fairly extensive and important pre-reading), you just follow the parental directions.