The Colorado legislature has recently taken school discipline policies under review, pursuant to SB 11-133. To inform the discussion in Colorado as well as a national discussion about discipline, this report presents an analysis of the most complete set of Colorado discipline data. It adds to and reinforces existing studies, documenting some troubling patterns, and suggests important changes in policy and in future data gathering. To accurately account for the fact that some students receive disciplinary actions more than once, this report describes and employs a measure that is called the "discipline assignment rate" in studying the proportion of students who receive discipline within certain population subgroups by gender and by race or ethnicity. Main findings from this analysis include: (1) Behavior categories that the authors identify as discretionary account for a combined 85.5% of yearly behavioral incidents, on average. These behaviors include disobedience, detrimental behaviors, and "other" violations; (2) Schools are, on average, more likely to assign out-of-school suspensions than any other disciplinary action. The next most common category is in-school suspensions; (3) Higher percentages of Black, American Indian, and Latino students receive disciplinary actions compared with White and Asian American students; (4) Disciplinary actions are assigned to Black students more than five times the rate of Asian American students and three times that of White students. The percentage of actions assigned to Black students is 36%, compared with a rate of 7% for Asian American students and 11% for White students; (5) Black students are assigned out-of-school suspensions at nearly four times the rate of White students, 21% compared with 5.5%. American Indian and Latino students are assigned out-of-school suspensions at over twice the rate of White students and over three times the rate of Asian American students; (6) Relative to students of color, when White students and Asian American students are subjected to discipline, schools tend to favor actions that do not push those students out of school; (7) The male discipline assignment rate is 21.7%, compared with a female rate of 8.2%; (8) Higher percentages of Black, American Indian, and Latino male students are assigned disciplinary actions compared with White and Asian American male students; (9) Higher percentages of Black, American Indian, and Latino female students are assigned disciplinary actions compared with White and Asian American female students; and (10) Past research has shown patterns in which certain racial groups are assigned discipline disproportionate to any race-identified differences in behaviors. The Colorado datasets do not allow for such analysis, however. Two key policy issues can be identified in this data. The first is whether racial disproportionality reflects a disproportionate number of students of color engaging in certain types of behaviors, or whether it reflects students of color being punished for behaviors that White students engage in without such serious consequences. The second issue involves out-of-school suspensions and the negative consequences, such as the higher dropout rates, correlated with this type of disciplinary action. The frequent use of out-of-school suspensions, and in particular the frequent use of this type of disciplinary action for students of color, needs to be remedied. Recommendations include: (1) Policy should be directed at decreasing the use out-of-school suspensions, which make up the majority of yearly actions and are linked to well-documented negative effects for students; policy also should be directed at decreasing the use of in-school suspensions; (2) Changes in discipline policy should take into account the overrepresentation of students of color in disciplinary actions; (3) Black, American Indian, and Latino youth are disproportionately affected by disciplinary practices. Colorado educators and lawmakers should immediately address the overrepresentation of students of color in disciplinary action, and changes in discipline policy must take into account racial disparity; (4) Policy should encourage increased examination of the effects of Positive Behavioral Interventions and Supports (PBIS) and Restorative Justice programs, such as mentioned in the recent report from the Legislative Task Force to Study School Discipline, as alternatives to traditional school discipline; (5) To enable improved analysis of disciplinary practices, policy should encourage the collection and reporting of school discipline data that include the student's behavior, the resulting disciplinary action, and the student's race and gender, all linked within the dataset; and (6) Further research on disciplinary practices should be supported, as many questions are still unanswered. Legislators and educators need to better understand what school characteristics are associated with higher overrepresentation as well as where in the disciplinary process overrepresentation is most apparent (e.g., in assigning actions or categorizing behaviors). Explanation of Colorado Discipline Data is appended. (Contains 13 tables, 1 footnotes and 22 notes and references.)