> For instance, after San Francisco Unified de-tracked math, the proportion of students failing algebra fell from 40 percent to 8 percent and the proportion of students taking advanced classes rose to a third, the highest percentage in district history.
This compares the number of 8th graders who failed Algebra 1 before the change to the number of 9th graders who failed Algebra 1 after the change. These are apples to oranges numbers. The appropriate metric is the percent of 9th graders that have passed Algebra 1 in either 8th or 9th grade before and after the change.
The following is arguably the most important metric that is omitted. From another article:
> While more students are taking precalculus now, the enrollment in Advanced Placement calculus courses has declined by nearly 13 percent over the past two years.