The article states: << The research team found that fifth graders' understanding of fractions and division predicted high school students' knowledge of algebra and overall math achievement, even after statistically controlling for parents' education and income and for the children's own age, gender, I.Q., reading comprehension, working memory, and knowledge of whole number addition, subtraction and multiplication

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It's kind of interesting that they controlled for a number of other potentially confounding factors, including skill (?) in simple arithmetic. But it is so hard to make accurate causal inferences. Anyone know what the state of the art in this is? --Dan Fred wrote: << Some comments about this article indicate ominously the traditional confusion between correlation and causation. No doubt some well-intentioned official will now become hell-bent on drilling children in long-division, on the entirely unsubstantiated assumption that this will improve their mathematics. One despairs ... Rich mentioned: << "Knowledge of Fractions and Long Division Predicts Long-Term Math Success" http://www.sciencedaily.com/releases/2012/06/120615114057.htm based on a CMU press release about the paper

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