Disproportionality is the inappropriate overrepresentation and over-identification of ethnic minority children in special education.  The disproportionality is in the relationship or association between a child's race or ethnicity and the type of special education classification and placement. 

How is disproportionality calculated?

• Disproportionality is commonly calculated using two statistical formulas: Chi Square and/or Relative Risk Ratio.
• Chi Square determines whether the observed (i.e., actual number of special education classification and placement for each racial or ethnic group) is significantly different from the expected (i.e., expected number of special education classification and placement for each racial or ethnic group based on enrollment). 
• Relative Risk Ratio determines the risk index in which ethnic minority students in comparison to White students are placed in special education settings and classified. 

How does disproportionality occur?

Disproportionality is a complex problem.  Research on disproportionality outlines a myriad of issues implicated in the relationship between race/ethnicity and special education classification and placement.  Some of these issues include cultural competency of teachers, pre-referral or early interventions, culturally appropriate assessment and instruction, home and school alignment, differentiated instruction, and classroom management.  In order to identify the root cause of disproportionality, schools and districts must engage in a problem-solving process in which multiple data is collected, analyzed, and interpreted in order to outline a plan for addressing disproportionality. 

What does IDEA (2004) outline regarding disproportionality?

The 2004 IDEA reauthorization stipulates that SEA and LEA will need to do several things: 1) design policies, procedures, and practices that prevent the overidentification of ethnic minority students; 2) collect and examine data on disproportionality; 3) review of policies, procedures, and practices; and 4) demonstrate models and scientifically-based research on practices that reduce disproportionality.

For more information:

http://www.ed.gov/policy/speced/guid/idea/tb-overident.pdf

http://thomas.loc.gov/cgi-bin/bdquery/z?d108:HR01350:@@@D&summ2=4&