The news in my state is going crazy (2) over the fact that SAT score average fell from 1493 to 1487 for this graduating class. I'm gonna go off on a limb here and say that a drop of .4% (.00402) is likely statistically insignifcant folks.
In fact, "Wayne Camara, vice president for research and analysis at the College Board, described the declines from 2006 to 2007 as statistically insignificant."
So, yes, the fact that Indiana lags behind the nation and is not closing that gap is a big issue, but a year-to-year change of such a small magnitude is not necessarily anything special. In fact, if SAT scores consistently rose every year without fail, assuming no major policy changes from year X to year X+1, that would tend to indicate that the class in year X+1 are always somewhat smarter than the class in year X, which of course is ridiculous - that should be pretty random year-to-year.
Hence, we would expect, holding policy and other shocks constant, SAT scores to go up and down and fluctuate ever so slightly over a number of years. And as policy changes, or tastes for education increase, etc, or real income rises.... we would hope to expect a gradual rise over the long-run ... somewhat akin to economic growth with recessions and booms (though not as dramatic). But the limits to SAT scores are much greater than for economic growth.
IE, we can't expect the average to keep climbing indefinately until it gets to a perfect score - that would be a waste of resources that could be devoted to healthcare, or defense or consumer spending other than education.
UPDATED to include total SAT score as opposed to just the reading portion.