Tests Scores and Affirmative Action

As time presses on, it seems that the number of standardized tests is increasing in America. While data for the rise of standardized tests is available because of government legislation ordering more examinations in public schools can be attributed to recent efforts such as No Child Left Behind (NCLB) in public schools, I wonder why tests that are administered by private companies like the ACT and the SAT are also increasing. Is it solely to increase profit or for another reason?

In an article from the March 17th New York Times, David Leonhardt writes that "only 34% of high-achieving high school seniors in the bottom fourth of income distribution attended any one of the country’s 238 most selective colleges". I find this especially interesting since almost 1/3 of 'high-achieving' hard working students cannot get into more selective institutions because I previously thought initiatives such as affirmative action highly encouraged colleges to accept a more diverse group of students.

However, the study published in the same article as above, the Hoxby-Avery economist paper, is clear to point out that low income does not imply the student is a minority.

It is common knowledge that many factors go into the college admission process; grades, extracurricular activities, and for some the all important test scores. One student cited by Leonhardt, Winona Leon, a sophomore at USC said that in her small town in Texas, "AP classes and SAT preparation were rare. It was really on ourselves to create those resources". There is definitely a correlation between the range of test scores and the amount of preparation taken. When preparation is 'rare' and the students are basically going into these high-stakes tests cold, the scores are not expected to be selective college quality. Given this, how is it fathomable for top colleges to increase the percentage of students from all backgrounds of income and race? Why is the relationship between private standardized test companies and affirmative action in college becoming more close-knit?