Washington’s Definition of Significant Disproportionality (WAC 392-172A-07040)
Washington defines SIGNIFICANT DISPROPORTIONALITY as a risk
ratio of >3.0 for three consecutive years for any racial/ethnic
group in any of the following areas:
A minimum “n” size is used for both target (10) and comparison groups (20).
- The identification of children as children with disabilities,
- The identification of children with a particular disability,
- The placement of children in particular educational settings or
- The incidence, duration, and type of disciplinary actions, including suspensions and expulsions.
The risk ratio is a measure of the risk that a student from a
specific racial/ethnic group will be served in a specific disability
category compared to the risk of all other students being served in that
category. For example, a risk ratio of 1.00 means that students
from that group are as likely to be served in the category as all other
students. A risk ratio greater than 1.00 indicates the degree to
which students in the racial/ethnic group are over-represented. Therefore, a
risk ratio of 3.23 in the EBD-Black category means that Black
students in the district are 3.23 times more likely to be identified in the
EBD category than all other students. A risk ratio less than 1.00
indicates the degree to which students from the racial/ethnic group are
under-represented. For example, a risk ratio of 0.50 in the ID-Hispanic category means that Hispanic students in the district are half as likely to be identified in the ID disability category as all other students.
Risk Ratio (RR)
*Note: The results of the calculations will be verified using multiple methods.
||>0.5 to <0.67
||0.67 to 1.5
||>1.5 to <2.0
||≥2.0 to <3.0
(3 consecutive years)
(3 consecutive years)
|Disproportionate Under- representation
||At Risk for Disproportionate Under-
||At Risk for
Disproportionate Over- representation
- Grade Level/Ages Served: Kindergarten through Grade 12.
- Groups Served: Only students who are not currently identified as needing special education or related services.
- Grade Level/Ages Served: Age 3 through Grade 12.
- Groups Served: Students who are not currently identified as needing special education or related services but who need additional academic or behavioral support to succeed in a general education environment; students currently identified as needing special education or related services (funds can be used primarily but not exclusively for this group).
- Bulletin 030-18: Changes in the Calculation of Significant Disproportionality, Under IDEA
- Fact Sheet: Equity in IDEA (USDOE, 12/12/16)
- Final IDEA Regulations on Disproportionality (Federal Register, 12/19/16)
- Model State Timeline and Gantt Chart for Significant Disproportionality Implementation (USDOE, PDF, 5/25/17)
- Significant Disproportionality (Equity in IDEA) Essential Questions and Answers (OSEP, 3/2017)
- Topic: Disproportionality and Success Gaps (IDEA Data Center)
- Summary Planning Worksheet
– Districts may use this worksheet as an optional self-review tool.
- List of disproportionality resources.
- Additional resources related to disproportionality
(Indicators 4, 9, and 10) can be found on OSPI’s
Disproportionality Technical Assistance
- Individual district data related to indicators 4, 9, and 10
can be found on the