Expelled Students in Need of Special Education Services Using Bayes’ Theorem: Implications for the Social Maladjustment Clause?

The purpose of the current study was to determine the probability that a student with a disability not being served by Individuals with Disabilities Education Act (IDEA) would be expelled. Expulsion data were obtained from the Civil Rights Data Collection produced by the U.S. Office of Civil Rights. The latest data from all 50 states and the District of Columbia for the 2017 to 2018 school year were analyzed. Bayes’ Theorem was used to determine this probability based upon existing probabilities and conditional probabilities. Analyses were also conducted by state and ethnicity. Results indicated that 1 in 14 of expelled students is likely to have an unserved disability under IDEA but variability according to race/ethnicity nationwide and by state was observed. Students who were White were the least likely to be an unserved student with a disability under IDEA among those expelled. The findings encourage investigation into the intersection of variables, especially the importance of including disability status and ethnicity when explaining disparate and punitive discipline. Practitioners, especially school psychologists, work at this intersection and can influence both special education identification and discipline practices.