Mapping Method - Equal Intervals
The range of data is divided into equally spaced intervals and the display shows how many states lie in each interval. This might display different numbers of states in each of the intervals. For example, "How many states have a risk ratio between 1 and 1.5?"
Mapping Method - Quintiles
The sample population is divided into five equal groups. Each group (called a quintile) represents 20% of the population with the 'highest' group representing the states with the highest numeric value for that indicator. For example, the 'highest' quintile for maps on disproportionality contains the states with the highest risk ratios, meaning the greatest over-representation. The 'lowest' quintile on these maps represents the states with the lowest levels of disproportionality which is usually 1, meaning equity, but in some case can be less than 1, indicating under-representation (you can see this by looking at equal intervals maps or the tables).
Outliers
Scores that are very high or very low in relation to the other scores in the distribution and which can skew the overall data. On this site we remove anything beyond 2 standard deviations from the mean. This leaves us with middle 95% of the data left to map. In cases where there are one or two states that have very high or very low values this will give us a more accurate picture for the remaining states.
Census Count Risk Ratio (vs. Whites)
The percentage of members of one racial/ethnic group who are in special education divided by the percentage of all white people aged 6-21 (from to the U.S. Census) who are in special education.
Census Count Risk Ratio (vs. Other Races)
The percentage of members of one racial/ethnic group who are in special education divided by the percentage of people aged 6-21 in all other race categories who are in special education. Census population data is from the yearly U.S. Census estimates.
School Child Count Risk Ratio (vs. Other Races)
The percentage of members of one racial/ethnic group who are in special education divided by the percentage of students in all other race categories who are in special education.
For example: If 20.5% of all black students are in special education and 10.2% of all other students are in special education, than 20.5 / 10.2 = 2.05, indicating that black students are 2.05 times more likely then other students to be in special education. Student enrollment data is compiled annually by the USDOE National Center for Education Statistics.
Racial Cluster
States are divided into groups based on their overall racial demographic.
  • Homogenous White: 85% or more white; 5% of less of any other group.
  • Predominantly Biracial: 45% to 65% white, 30% or more African American, 5% or less of any other group.
  • Moderately Biracial: 60%-85% white, 15% or more AA, 5% or less of any other group.
  • Predominantly Multiracial: non-white races account for 40% or more, 3 or more races have at least 10%.
  • Moderately Multiracial: non-white races account for 20% -39% or more, 3 or more races have at least 5%.
  • White-American Indian: white and AI account for 80% or more ofthe population and AI is at least 5%.
  • White-Hispanic: white and hispanic account for 85% or more or pop and hispanic is at least 10%.
  • Other: none of the above.
School Age Population
Total number of people age 6-21 based on the 2000 Census.
IDEA Part B Population
Number of students enrolled in IDEA Part B.
School Year

Data is organized on this website by the school year that is nearest to the date of the data snapshot. The follow table shows the snapshot dates of each of our data sources and the school year that the data will be associated.

Source DataSnapshot DateSchool Year
U.S. Census Est. Population CountsJul. 1, 20042004-2005
OSEP Special Education Student CountsOct. 31 or Dec. 1, 20042004-2005
NCES Overall Student CountsSchool day closest to Oct. 1, 20042004-2005
title2.org* Teacher Certification/LicensureOct. 1, 20042004-2005

* The year shown on the title2.org reports is the year the report was presented to Congress. States are required to report data to the U.S. Department of Education in October of the year previous to the report date. The states are required to collect the data on October 1st one year previous to the repoting deadline. This means that the 2005 Title II Report to Congress will contain data for the 2003-2004 school year.

Least Restrictive Environment
Before 2006 the catgegories "Inside Regular Class 40% to 79% of Day", "Inside Regular Class 80% or More of Day", and "Inside Regular Class Less Than 40% of Day" were called "Outside Regular Class 21% - 60% of Day", Outside Regular Class < 21% of Day", and "Outside Regular Class > 60% of Day" respectively.