First, Karl Popper tells us that collecting data and analysing it cannot show or prove something to be true, it can only reveal that our ideas may not hold true in some situations. So the only research we need consider is that which shows our cherished beliefs may be wrong and need rethought.
Second, schools do not allow for the design of controlled experiments where all other variables are held constant. You cannot even sort out children into two identical classes. So we can dismiss results that are open to other influences.
Third, you cannot adopt blind or double blind scenarios. The teachers know which scheme they are using. Suppose they feel they like one and think it will work. That feeling would be enough to make a real researcher dismiss the result as possibly corrupted.
Fourth, the old Harvard studies at the Hawthorne works showed that becoming interested in an area by itself increased production in that part of the works. Medical research knows, too, that novelty or a placebo effect is so great it is hard to identify clinical responses to drug treatment.
Fifth, children don't learn to read by being taught, whatever that means.
They learn by actively thinking, doing something inside their own brains.
Who is so bold as to believe they really understand the complexity of this process?
Sixth, there is a lot to be gained by thinking this all through and matching approaches to the children in front of us rather than being told (again) what to do.