Most teachers and principals don’t have a lot of time to pour over the latest data from the National Assessment of Educational Progress long-term trend assessment, The Huffington Post reports. That’s too bad, because the results from this “gold standard” national examination provide overwhelming evidence that the blood, sweat, and tears that many have poured into helping their children achieve at higher levels has paid off spectacularly for their students. Despite the constant cry that American schools are in decline, these results suggest they have never been better. At the elementary and middle school levels, overall results are up substantially, and at all ages, they are up for every group of children: white, black, and Latino…