[oldbuzzard]

The article addresses that a couple of paragraphs down. Thats her whole point.To quote:

"The Nation at Risk report that started it all turned out to be bullshit, by the way -- grounded in another laughable statistical error. Sandia Labs later audited the findings from the report and found that the researchers had failed to account for the ballooning number of students who were taking the SATs, bringing down the average score.

In other words: SATs were falling because more American kids were confident enough to try to go to college: the educational system was working so well that young people who would never have taken an SAT were taking it, and the larger pool of test-takers was bringing the average score down."

[trendia]

I was converting her text into math-ish notation. She's saying that

P(SAT Score > 700 | 1970) > P(SAT Score > 700 | 1980)

is inaccurate, and that we should instead use:

P(SAT Score > 700 | cohort, 1970) ~ P(SAT Score > 700 | cohort, 1980)