Discipline Disproportionality

Risk ratio. A group's risk is the share of its students with at least one event. The risk ratio divides that by the risk for all other students. 1.0 means even. 2.0 means twice as likely.

Likely range. The 95% range for the ratio (Katz log method). The underlying ratio is most likely in that span. A range that includes 1.0 means an even split is still possible.

When the tool calls it disproportionate. Only when the whole likely range sits above 1.0 and the ratio reaches the line you set (2.0 unless you change it). These lines are this site's guide, not federal rules: under 0.8 less likely, 0.8 to 1.25 near even (slightly higher or lower when the whole range sits on one side of 1.0), 1.25 up to your line worth a closer look, your line or more disproportionate, 3.0 or more highly disproportionate.

Too few to call. With fewer than 10 students with an event in the group, or fewer than 30 students on either side, the tool shows the numbers but makes no call. One or two students would swing the ratio. When only the comparison group has fewer than 10 events, which is common for expulsions, the tool still makes the call if even the low end of the likely range reaches your line, and says the exact ratio is loose.

Share is a different number. "20% of students and 33% of students suspended" compares shares. It is useful, but it is not the risk ratio. A group that is 10% of students and 30% of students suspended has a risk ratio of about 3.9, not 3.

IDEA reviews. Federal significant disproportionality reviews use this same kind of risk ratio, but for students with disabilities, by race and ethnicity, at the district level, over several years, with thresholds each state sets. When the comparison group is small, those reviews use a statewide comparison instead. This page starts a conversation about systems and adult decisions. It is not a compliance finding.