high school for four years. Students may obtain a GED, a certificate of attendance, or another alternative type of diploma. They may take longer than the typical 4 years before completing high school and may transfer across schools or districts before graduating or dropping out. There are a variety of strategies for accounting for these factors in calculating dropout, completion, and graduation rates; different strategies will affect the appropriateness of the rate for a given purpose. Thus, decisions about how to handle these factors should be consistent with the purpose for calculating the rate.

For example, if the purpose is to describe the level of education of the population, what matters is people’s eventual level of education, not what kind of diploma they received or how long it took them to earn it. But if the purpose is to evaluate a school’s effectiveness in graduating students in 4 years, those factors are of critical importance. All methods for calculating the rates require decisions about who to include in the numerator and denominator of the rate and how to handle certain groups of students, such as those who receive a GED or who take longer than four years to graduate.

We recommend that analysts and users keep their purpose in mind when selecting from among the various kinds of rates and choose the indicator best suited to that purpose (Recommendation 4-11). To help users draw sound conclusions, analysts should document the limitations of the rate and the decisions that went into calculating it (Recommendations 3-1 and 3-2). When the limitations are made explicit, alternative rates can be calculated to verify any conclusions drawn from the statistic (Recommendations 3-3 and 3-4).

The most accurate rates are those based on longitudinal data that track students over the course of their schooling, and we recommend that dropout and completion rates be based on individual student-level data whenever possible. This will allow for the greatest flexibility and transparency with respect to how analysts handle methodological issues that arise in defining the numerator and denominator of the rates (Recommendation 4-2).


Calculating rates based on individual data requires that states have a system for tracking students over time. At a minimum, such a system needs unique student identifiers as well as complete information on students’ enrollment status throughout high school. However, a more comprehensive system would incorporate data elements that allow school systems to monitor students’ progress, identify students at risk of dropping out, and evaluate the effectiveness of programs to reduce dropping out. To perform these functions, data systems require detailed longitudinal data (Recommendation 6-1).


Recommendation 4-1 is the first recommendation in Chapter 4. Other recommendations are numbered accordingly.

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