You've gotta wonder how a nation's schooling standards shift to something like "Whole language" without, say, at least testing the methodologies to see if it results in better or worse outcomes. Seems like no actual validation was done.
As the sibling comment mentions, it was tested. It got tied up in some weird politics and the George W. Bush administration was championing evidence based reading programs so teaching programs at places like Colombia took the opposite stance. Obviously that's a bit of an oversimplification, but you get the idea.
They did test it: see Project Follow Through. They didn't like the results, so they ignored them.