cannot resolve moral conflicts, but it can help to more accurately frame the debates about those conflicts.
Heinz Pagels

Using data


The first step in addressing inequitable outcomes in education is to clearly recognize that disparities by race and ethnicity continue to exist. In order to come to that recognition, it is necessary to have a standard set of measures of disproportionality in order to provide an agreed upon baseline describing the extent of current disparities.

How do we measure whether disproportionality exists?

Although the concept of disproportionate representation seems relatively straightforward, measurement of disproportionality can be quite complex. In measuring disproportionality, one may assess a) the extent to which a group is over- or under-represented in a category compared to their proportion in the broader population (composition index) or b) the extent to which a group is found eligible for service at a rate differing from that of other groups (risk index and risk ratio).

What is the composition index?

The most intuitive method of measurement of disproportionality, the composition index (CI)[1], compares the proportion of those served in special education represented by a given ethnic group with the proportion that group represents in the population or in school enrollment; that is, it provides a measure of representation in the target phenomenon compared to our expectations for that group. At the national level, African-American students account for 33% of students identified as mentally retarded, clearly discrepant from their representation in the school-aged population of 17%.

What is the risk index?

An alternative to the composition index for describing disproportionality is to measure a group's representation in special education compared to other groups. The risk index (RI) is the proportion of a given group served in a given category and represents the best estimate of the risk for that outcome for that group. Donovan and Cross (2002) reported for example that, at the national level, 2.64% of all African-American students enrolled in the public schools are identified as mentally retarded.

How is the risk index interpreted?

By itself, the risk index is not particularly meaningful. In order to interpret the risk index, a ratio of the risk of the target group to one or more groups may be constructed, termed a risk ratio (RR).[2] A ratio of 1.0 indicates exact proportionality, while ratios above or below 1.0 indicate over- and under-representation, respectively. Comparing African-American risk for MR identification (2.64%) with the risk index of 1.18% of White students for that disability category yields a risk ratio of 2.24 (2.64/1.18), suggesting that African Americans are over two times more likely to be served in the category mental retardation than White students.

Are there any guidelines for calculating measures of disproportionality?

In order to aid states in the reporting of disproportionality data, the U.S. DOE Office of Special Education Programs and Westat convened a national panel to consider methodologies for monitoring disproportionality. Guidance developed as a result of that panel: a) recommends the use of a risk ratio approach to measure disproportionality; b) provides guidance on the calculation of those measures; and c) recommends an alternative "weighted" risk ratio when there are fewer than 10 students from a target group in a given school district, or to compare risk ratios across districts.[3][4] Absolute criteria for significant disproportionality are left undefined by federal guidelines however, in order to allow each state to set its own guidelines.

What are factors that need to be kept in mind in interpreting data?

The effectiveness of an intervention chosen to address disproportionate representation depends, to some degree, upon the accuracy of diagnosis of the causes of disparity. Early intervention appears to be an extremely promising intervention for a range of developmental issues related to socioeconomic disadvantage.[5] Yet early intervention approaches could be expected to reduce disparities only to the extent that economic disadvantage is at work. Early intervention would not be expected to address systemic failures or bias and would, hence, fail to address disproportionality due to institutional inequity.

Unfortunately, interpretation of data on differential racial treatment itself appears to be conditioned by race. A number of authors have noted that it is common for interpretations of equity data to be based on a majority viewpoint.[6][7] Recent history from the Simpson trial to reactions to Hurricane Katrina indicate that, at this point in our nation's history, interpretations of data on racial and ethnic disparities will vary depending on the cultural makeup of the audience confronting the data. Thus, educators and policymakers seeking effective interventions to close special education equity gaps must be willing to openly discuss and address issues of race, ethnicity, gender, class, culture and language. Moreover, processes chosen to address inequity must have at their core a mechanism to ensure that the perspectives of all stakeholders, especially those of historically marginalized groups who have been the recipients of unequal treatment, are represented when interpreting data on racial and ethnic disparities. The next section, Talking About Race, discusses both the difficulty and the critical importance of directly and openly addressing the topic of race in education.

See also: Skiba, R. J., Simmons, A. D., Ritter, S., Gibb, A., Rausch, M. K., Cuadrado, J., & Chung, C. G. (2008). Achieving equity in special education: History, status, and current challenges. Exceptional Children. Download.


  1. Donovan, M. S., & Cross, C. T. (Eds.). (2002). Minority students in special and gifted education. Washington, D.C.: National Academies Press.
  2. Hosp, J.L., & Reschly, D.J. (2003). Referral rates for intervention and assessment: A meta-analysis of racial differences. Journal of Special Education, 37, 67-81.
  3. Westat (2004). Summary of task force meeting on racial/ethnic disproportionality in special education. Washington, D.C.: Author.
  4. Westat (2005). Methods for assessing racial/ethnic disproportionality in special education: A technical assistance guide. Washington, D.C.: US Department of Education Office of Special Education Programs. (Downloaded October 5, 2006 from IDEAdata.org, direct link to document here).
  5. King, J.E. (Ed.) (2005). Black education: A transformative research and action agenda for the new century. Mahwah, NJ: Lawrence Erlbaum Associates for the American Educational Research Association.
  6. Patton, J. M. (1998). The disproportionate representation of African Americans in special education: Looking behind the curtain for understanding and solutions. The Journal of Special Education, 32(1), 25-31.
  7. Parrish, T. (2002). Racial disparities in the identification, funding, and provision of special education. In D. J. Losen & G. Orfield (Eds.), Racial inequity in special education. Cambridge, MA: Harvard Education Press.

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