The accuracy of data driven decisions depends entirely on 
the appropriateness of the data being used. Relying on standardized test scores to determine career and college readiness of students is like a doctor using a student’s report card to diagnose the flu.
“…New research findings suggest a significant portion of students who test into remedial classes don’t actually need them…”
The way colleges are using standardized placement tests such as the College Board’s Accuplacer, ACT’s Compass, and others can misidentify students.
According to the most recent data from the National Center on Education Statistics, 3 million new students enter higher education each year, and fully half take at least one catch-up course while they are enrolled—at a cost of nearly $7 billion a year for the noncredit-bearing classes…
Those high rates of remediation have long been used by education policymakers to suggest that primary and secondary schools do not prepare students adequately for college-level work. They were one of the key arguments behind the development of the common core and other standards-reform initiatives.
“It’s being used in some places for high school accountability, so this certainly raises a word of caution,” said Ms. Scott-Clayton. “We can’t just take the remediation rate as purely objective and without problems. Is this accountability gone awry?”
“So much focus and attention is on the students who are not succeeding, and how to help them succeed, that there just was not much talk about, ‘Hey, maybe there are some people in remediation who don’t need to be there,'” Ms. Scott-Clayton said.
“The high school transcript info is basically more accurate for every group we look at,” Ms. Scott-Clayton said. “It’s true that it’s more subjective, but you are getting multiple measurements accumulated over time across several instructors. And it is capturing a broader array of skills, not just pure mechanical test-taking skills, but effort, persistence, motivation—things that we know matter a lot for college success.”
Source: Education Week 2/19/13, “Many Students Don’t Need Remediation, Studies Say”
http://www.edweek.org/ew/articles/2013/02/20/21remediation_ep.h32.html