The purpose of this memorandum is to provide Massachusetts school districts and other interested parties with updated guidance regarding the Commonwealth's methodology for determining significant disproportionality under the Individuals with Disabilities Education Act (IDEA). This memorandum outlines the annual determination process, recent revisions to the state's calculation methodology, district responsibilities following identification, and the technical assistance and supports available through the Department.
Massachusetts remains committed to ensuring equitable educational opportunities for all students. Significant disproportionality determinations are intended to identify districts where persistent patterns of inequitable outcomes based on race or ethnicity warrant further review of district policies, practices, and procedures, as required under Individuals with Disabilities Education Act IDEA.
Individuals with Disabilities Education Act IDEA requires every state to annually determine whether significant disproportionality based on race or ethnicity exists within school districts in the areas of:
These annual identifications are intended to identify districts exhibiting meaningful and sustained disparities rather than isolated year-to-year fluctuations.
Massachusetts periodically reviews its methodology to ensure that it:
The methodology2 revisions described in this memorandum support these goals while maintaining Massachusetts' commitment to educational equity.
Consistent with Individuals with Disabilities Education Act IDEA regulations (34 Code of Federal Regulations CFR §§300.646–300.647), Massachusetts annually calculates risk ratios for each district across all federally required categories of analysis.
Each racial or ethnic group is compared to all other students within the district for each required category. When there are insufficient students in the comparison group, the Department calculates an Alternate Risk Ratio using statewide comparison data, as required by federal regulations.
To determine whether a district demonstrates significant disproportionality, Massachusetts reviews:
A district is identified only when the established methodology indicates a persistent pattern of disproportionate outcomes that meets all applicable criteria.
Following an extensive review of Massachusetts data, stakeholder feedback, and national practices, the Department has revised one component of the state's approved methodology.
Beginning with the 2026–2027 annual significant disproportionality identifications, Massachusetts will increase the minimum cell size from six (6) students to ten (10) students.
The minimum cell size represents the minimum number of students within a racial or ethnic group experiencing a particular outcome before a risk ratio is calculated.
Increasing the minimum cell size improves the statistical reliability of the methodology by reducing the influence of year-to-year fluctuations caused by one or two students in very small populations. This revision allows the Department to focus identification on districts demonstrating more stable and sustained patterns of disproportionality while reducing unintended identification of districts with very small student groups.
The Department's methodology continues to include:
The only change to the methodology is the increase in the minimum cell size from six to ten students.
Massachusetts continues to recognize that districts demonstrating sustained improvement should not necessarily be identified with significant disproportionality.
The Department will continue applying its reasonable progress standard when reviewing three years of data. Districts demonstrating sufficient improvement in reducing risk ratios over the three-year review period may not be identified, even if the risk ratio threshold is exceeded in each year.
Each year, the Department follows a consistent statewide process to determine significant disproportionality.
The annual process includes:
All districts receive their annual significant disproportionality calculations regardless of whether they are identified.
Districts identified with significant disproportionality must complete the actions required under Individuals with Disabilities Education Act IDEA.
These include:
Identification with significant disproportionality is not a finding of noncompliance with Individuals with Disabilities Education Act IDEA. Rather, it initiates a structured review process intended to support continuous improvement and equitable outcomes for students.
The Department is committed to partnering with districts throughout the improvement process.
Districts identified with significant disproportionality will receive technical assistance that includes:
The Department's goal is to assist districts in addressing the underlying factors contributing to disproportionality while building sustainable systems that promote equitable outcomes for all students.
In addition to supporting districts identified with significant disproportionality, the Department will continue providing proactive supports to districts demonstrating elevated risk ratios over multiple years.
Districts that are at risk of identification may be invited to participate in targeted technical assistance activities designed to strengthen local capacity before federal identification occurs. These supports may include webinars, facilitated root cause analysis, review of district policies and practices, and action planning resources intended to reduce future risk.
These proactive supports are voluntary and are intended to help districts address emerging trends before significant disproportionality is identified.
The annual significant disproportionality process generally follows the timeline below.
The Department encourages districts to review the following resources available on the Department's Significant Disproportionality webpage:
Additional guidance documents will continue to be published as the Department refines resources to support districts. If you have additional questions related to Significant Disproportionality, please contact the Department at IDEAData@mass.gov .
1 34 Code of Federal Regulations C.F.R. §300.646(a)
2 34 Code of Federal Regulations C.F.R. §300.647
3 34 Code of Federal Regulations C.F.R. §300.646(d)(1)(iii)
4 34 Code of Federal Regulations C.F.R. §300.646(d)
Last Updated: September 4, 2026