Gap Finder

Everyone else. Each group is compared with all students who are not in it. Their rate comes from the all-student numbers: (all-student rate times all students, minus the group's rate times the group's students) divided by the students left. Comparing a group with an average that includes the group hides part of its gap, most of all for big groups, so the tool never does that.

Clear gap. A real test, the same one Is This Difference Real? uses: the 95% likely range for the gap (Newcombe score method) does not include zero. "Too close to call" means it does. A clear gap on the better side is shown in blue, because only the concern side gets the concern color.

Students. "About 111 more students" is the group's size times its gap from everyone else: how many more students are in the outcome than if the group had everyone else's rate. Groups overlap (a student can be in several), so these counts are never added together.

Small groups. Groups under 10 students are listed by name without a rate and never ranked. A rate on a handful of students swings too far to compare, and many states hide groups that small for privacy.

What a gap means. A gap describes what the system produced for a group, not a cause and not a verdict on the students in it. The useful question is what is different about that group's experience of school, and what adults can change.