Various measures have been developed to provide information about student persistence and progress through formal elementary and secondary education in the United States. Three measures are presented in this report: the public school averaged freshman graduation rate (indicator 19), the status dropout rate(indicator 20), and the educational attainment of 25- through 29-year olds (indicator 23). Each of these indicators employs a different analytic method and dataset to document a unique aspect of the complex high school graduation and dropout processes. No single data source provides comprehensive information on the graduation and dropout processes on an annual basis, but the three indicators presented here complement one another and draw upon the particular strengths of their respective data. Each indicator has limitations, however, which underscores the importance of having multiple indicators when addressing the question of student persistence. A brief description of the relevant methodology and data used by each indicator follows.

Public School Averaged Freshman Graduation Rate

Indicator 19 examines the percentage of public high school students who graduate on time by using the averaged freshman graduation rate (AFGR). The AFGR is a measure of the percentage of the incoming freshman class that graduates 4 years later. The AFGR is the number of graduates with a regular diploma divided by the estimated count of incoming freshmen 4 years earlier as reported through the NCES Common Core of Data (CCD), the survey system based on state education departments' annual administrative records. (For more information on the CCD, see supplemental note 3.) The estimated count of incoming freshmen is the sum of the number of 8th-graders 5 years earlier, the number of 9th-graders 4 years earlier (when current year seniors were freshmen), and the number of 10th-graders 3 years earlier, divided by 3. The intent of this averaging is to account for the high rate of grade retention in the freshman year, which adds 9th-grade repeaters from the previous year to the number of students in the incoming freshman class each year. Ungraded students are allocated to individual grades proportional to each state's enrollment in those grades. An advantage of using CCD data to calculate the AFGR is that the data are available on an annual basis by state; however, the demographic details available from the survey are limited.

Status Dropout Rate

Indicator 20 reports status dropout rates by race/ethnicity and nativity status. Status dropout rates measure the extent of the dropout problem for a population. As such, these rates can be used to gauge the need for further education and training within that population. Indicator 20 uses data from the American Community Survey (ACS) and the October Current Population Survey (CPS) to estimate the percentage of the population ages 16 through 24 who are not in high school and who have not earned a high school credential (either a diploma or an equivalency credential such as a General Educational Development [GED] certificate), irrespective of when they dropped out. The 2007 ACS allows for more detailed comparisons of status dropout rates by race/ ethnicity, nativity, sex, and, unlike the CPS, includes institutionalized persons, incarcerated persons, and active duty military personnel living in barracks in the United States. The CPS provides several decades of historical trends on status dropouts that are not available from the ACS. The disadvantage of using CPS data to compute status dropout rates for the civilian, noninstitutionalized population is that all military personnel living in barracks and incarcerated or institutionalized persons are excluded. A disadvantage of both the CPS and ACS is that the data-sets include as dropouts individuals who never attended U.S. schools, including immigrants who did not complete the equivalent of a high school education in their home country. Estimates of status dropout rates from the ACS and CPS are not directly comparable due to methodological differences, such as differing sampling frames, modes of administration, and question wording. For more information on the CPS, see supplemental note 2, and for more information on the ACS, see supplemental note 3.

Educational Attainment of 25- to 29-Year-Olds

Indicator 23 examines the educational attainment of adults just past the age when most would traditionally be expected to have completed their postsecondary education. This indicator uses March CPS data to estimate the percentage of civilian, noninstitutionalized people ages 25 through 29 who have achieved the following levels of educational attainment: high school diploma or equivalent (including a credential such as a GED), some college, bachelor's degree, or master's degree. Estimates of educational attainment represent the percentage of adults who completed at least the cited credential. Attainment estimates do not differentiate among those who graduated from public schools, who graduated from private schools, or who earned a GED. These estimates also include individuals who never attended high school in the United States but attained a high school diploma or its equivalent in another country. An advantage of using CPS data to compute educational attainment estimates is that estimates can be computed on an annual basis for various demographic subgroups of adults. A disadvantage of using CPS data to compute the educational attainment rate is that these data exclude all military personnel living in barracks and incarcerated or institutionalized persons. For more information on the CPS, see supplemental note 2.

Conclusion

Even though indicators 19, 20, and 23 document different aspects of student persistence, a number of important differences between these indicators should be noted and recognized as likely factors responsible for the divergence between their respective estimates. General differences can be found in the population of interest, information source, and data collection time frame. For example, the three indicators mentioned above focus on different populations: indicator 19 focuses on the number of graduates in 2005-06 based on the 2002-03 freshman class; indicator 20 focuses on 16- through 24-year-olds between 1980 and 2007; and indicator 23 focuses on 25- through 29-year-olds in selected years between 1971 and 2008. As noted above, the data sources used to construct the indicators are also different. Indicator 19 is produced from the CCD, a universe survey system based on state education departments' annual administrative records; indicators 20 and 23 use data from the CPS, a sample survey of the civilian, noninstitutional population; and indicator 20 uses data from the ACS, a sample survey of the population including institutionalized persons.

Given such differences, one would not expect to see identical or even similar estimates. In fact, reasonable differences should be apparent. For example, if one estimate measures only regular diplomas completed on time, it should be smaller than an estimate constructed to measure both regular diplomas and GEDs obtained outside of the regular 4-year "on-time" period. Once accounting for these methodological differences are accounted for, the divergence between estimates tends to be in the correct direction and of the right magnitude.

This supplemental note is intended to provide only a brief overview of some of the commonly available data that address issues of high school completion and educational attainment. For other related measures of student persistence and progress, see the publications by Seastrom et al. (NCES 2006-604; NCES 2006-605) and Laird, DeBell, and Chapman (NCES 2007-024).