Throughout this report, we use several terms that warrant clarification. We use the term “graduate” to refer to a student who earns a regular high school diploma and “graduation rate” as an indicator of the percentage of students in a given population who earned a regular high school diploma. We note, however, that the definition of “regular diploma” may vary as well as the time allowed to complete it. We use the term “completer” as the all-encompassing term to refer to a student who finished high school via one of multiple ways, such as by earning a regular high school diploma, a GED, or another type of certificate (a certificate of attendance, certificate of completion, etc.). Likewise, “completion rate” indicates the percentage of students in a given population who finished high school in any of these ways. We use the term “dropout” to refer to a student who did not complete high school and “dropout rate” as an indicator of the percentage of students in a given population who did not complete high school. Dropouts may include those who earn a GED or an alternative credential (depending on the specific indicator or the purpose of the indicator), but the group does not include students still enrolled in school after they were expected to complete. There are a number of policy definitions of these terms that further specify them (e.g., NCLB specifies that the graduation rate should include only on-time diploma earners, and it classifies GED recipients with dropouts). Unless otherwise specified in the report, we use the terms in their most general sense.
There are four general categories of dropout/completion indicators, which are defined below.
Individual cohort rate: a rate derived from longitudinal data on a population of individuals who share a common characteristic at one point in time, such as entering high school. The rate is based on tracking the students over the 4 years of high school or more to determine which of them graduated and which of them dropped out.
Aggregate cohort rate: a rate designed to approximate an individual cohort rate when longitudinal data are not available by using aggregate counts of students (e.g., number of ninth graders in a given year, number of graduates in a given year). For instance, an aggregate cohort rate might compare the number of students who graduate in one year with the number of students who entered high school 4 years earlier.
Status rate: a rate that represents the fraction of a population that falls into a certain category at a given point of time (e.g., the percentage of the total U.S. population that does not have a high school diploma).
Event rate: a rate that is the fraction of a population that experiences a particular event over a given time interval. For instance, the event dropout rate indicates the percentage of students who exit school during a specific academic year without having earned a diploma.