Significant Disproportionality
Washington’s Definition of Significant Disproportionality (WAC 392172A07040)
Washington defines SIGNIFICANT DISPROPORTIONALITY as a weighted risk
ratio of 4.0 or greater for three consecutive years for any racial/ethnic
group in any of the following areas:
 The identification of children as children with disabilities,
 The identification of children with a particular disability,
 The placement of children in particular educational settings (LRE Tables 2, 3, 28, or 29), or
 The incidence, duration, and type of disciplinary
actions, including suspensions and expulsions.
A minimum “n” size is used for both target and comparison groups.The weighted 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 weighted 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 weighted risk ratio greater than 1.00 indicates the degree to
which students in the racial/ethnic group are overrepresented. Therefore, a
weighted risk ratio of 4.17 in the EBDBlack category means that Black
students in the district are 4.17 times more likely to be identified in the
EBD category than all other students. A weighted risk ratio less than 1.00
indicates the degree to which students from the racial/ethnic group are
underrepresented. For example, a weighted risk ratio of 0.50 in the IDHispanic category means that Hispanic students in the district are half as likely to be identified in the ID disability category as all other students.
Weighted Risk Ratio (WRR)
≤0.5 
>0.5 to <0.67 
0.67 to 1.5 
>1.5 to <2.0 
≥2.0 to <3.0
(3 consecutive years) 
≥3.0 to <4.0
(3 consecutive years) 
≥4.0
(3 consecutive years) 
Disproportionate Under representation 
At Risk for Disproportionate Under
representation 
No Disproportionate
Representation 
At Risk for
Disproportionate Over representation 
Disproportionate Over
representation* 
At Risk for Significant
Disproportionality 
Significant
Disproportionality* 
*Note: The results of the calculations will be verified using multiple methods.
Resources:
 Summary Planning Worksheet
– Districts may use this worksheet as an optional selfreview tool.
 Additional resources related to disproportionality
(Indicators 4, 9, and 10) can be found on OSPI’s
Disproportionality Technical Assistance
Web page.
 Individual district data related to indicators 4, 9, and 10
can be found on the
District Profiles.

