The failure of targeting data

I wrote last week about the dangers of targeting data rather than the underlying conditions that serve as the cause for the data.   Jay Mathews of the Washington Post then wrote about this policy at West Springfield High in Virginia.  The school provides some type of review session for students in need remediation.  That sounds benign enough- except that while a small percentage of students attend these sessions, the rest of the school is left to litterally, do whatever they please:

Fairfax high schools have different names and schedules for the periods. At West Springfield, two 45-minute sessions a week are used to help the 10 percent or so of students in danger of flunking Virginia's Standards of Learning exams.

The decision made above is not one that was made in a vaccuum.   Rather, this is symptamatic of the way data drives narrowly tailored decision making across the country.   Often, this type of decision making drives data driven results that are celebrated as successes.   Yet little is done to consider  the cost of such decision- making.   Are the students at West Springfield High School better off for a policy where 90% of the student body sits idle?   I am inclined to think the answer is no.