During the 1999–2000 school year, a total of about 3,450,000 teachers worked in public and private elementary and secondary schools across the country—representing about 2.7 percent of the overall U.S. workforce that year.⁴ Elementary and secondary school teachers constituted a greater percentage of the workforce than physicians (0.5 percent), legal professionals (0.8 percent), postsecondary faculty (0.9 percent), engineers (1.0 percent), firemen and law enforcement workers (1.0 percent), registered nurses (1.5 percent), or any other professional group that year. Elementary and secondary school teachers constituted about the same percentage of the workforce as all secretaries and administrative assistants (2.7 percent) and slightly less than retail workers (2.8 percent) (U.S. Department of Labor 2002). The statistics that follow attempt to profile this large workforce by describing its basic features and its distributions of demographic and professional characteristics.

The majority of teachers (90 percent) worked full time, 4 percent worked part time, 3 percent were itinerant teachers, and less than 0.5 percent worked as long-term substitutes.⁵ Eighty-seven percent (3,000,000 teachers) worked in public schools, and 13 percent (450,000 teachers) worked in private schools.⁶

As has historically long been true in the United States, females made up the majority of the teacher workforce in 1999–2000: a total of 2,590,000 teachers were female, while 860,000 teachers were male (75 vs. 25 percent). The percentages of female and male teachers were similar in both public and private schools: female teachers made up 75 percent of public school teachers and 76 percent of private school teachers. However, the distribution of teachers by sex differed widely by grade level. Among those teaching in the elementary grades, 1,340,000 teachers were female, while 140,000 teachers were male (91 vs. 9 percent). In contrast, at the high school level, 570,000 teachers were female, while 470,000 teachers were male (55 vs. 45 percent). In the middle grades, there were 660,000 female and 250,000 male teachers (73 vs. 27 percent).⁷

The average age of brand-new teachers in 1999–2000 was 29 years old (the median was 26 years old), suggesting that many teachers do not enter the teacher workforce in their early twenties—an age that is traditionally associated with being “right out of college.” The average age of all elementary, middle, and high school teachers was 42 (the median was 44 years old).⁸ About 29 percent of teachers were under age 35, 42 percent were ages 35–49, and 29 percent were age 50 or older (see figure 1 for further detail).

The average number of years of teaching experience for all teachers was 14 years in 1999–2000. More than one-third of teachers (36 percent) had 19 or more years of teaching experience, 24 percent had 10–18 years, 24 percent had 4–9 years, and 17 percent had 3 or fewer years (see figure 2 for further detail). As this analysis will show, many teachers leave the teaching profession for a period of time for various reasons, and some enter it later in life. As a result, many older teachers have less teaching experience than one might expect. For example, 19 percent of teachers between the age of 45 and 49 in 1999–2000 had less than 10 years of teaching experience, and 9 percent of teachers between the age of 50 and 59 had less than 10 years of teaching experience.

In 1999–2000, the highest degree attained for the majority of teachers (53 percent) was a bachelor’s degree. Forty-two percent of teachers had attained a master’s degree as their highest degree, and 4 percent had attained a doctorate, professional, or education specialist degree. Less than 2 percent of all teachers had completed no more than an associate’s degree.

Although teachers’ academic degrees and their average years of experience have been traditional indicators of the qualifications of the teacher workforce, research has not found the highest degree attained by teachers to be a good predictor of gains in student achievement (Rivkin, Hanushek, and Kain 2005; also see Hanushek 1996; Hedges, Laine, and Greenwald 1994). Number of years of teaching experience has also proven to be problematic in predicting such gains. Generally, beginning teachers (those with 3 or fewer years of teaching experience) are not as effective as teachers with more years of teaching experience, with brand-new teachers typically being the least effective teachers (Rivkin, Hanushek, and Kain 2005; Rockoff 2004; Murnane 1975). Research has consistently found that brand-new teachers make “important gains in teaching quality in the first year and smaller gains over the next few career years”; however, there is not a consistent linear relationship between years of teaching experience and student achievement after the initial three years of teaching, making it difficult to say whether there are any discernible differences among more veteran teachers—for example, between teachers with 7–10 years of experience and teachers with 20 or more years of experience (Rivkin, Hanushek, and Kain 2005, p. 449; Murnane and Phillips 1981). A better predictor of student achievement—and hence a better indicator of the qualifications of the teacher workforce—is whether teachers have training and certification in the field they teach (Monk 1994; Goldhaber and Brewer 1997, 2000). Those who have neither an undergraduate or graduate major nor certification in the field they teach are known as “out-of-field” teachers. Research has suggested that high school students in mathematics and science learn less from out-of-field teachers than they do from teachers with a major or certification in the field they teach (Goldhaber and Brewer 1997, 2000; for a summary of this research, see Seastrom et al. (2002), pp. 1–2).

In 1999–2000, among all teachers at all grade levels, an average of 12 percent were teaching out-of-field in their main assignment area; however, this percentage varied greatly by school control, subject area, and level.⁹ For example, 30 percent of private school teachers taught out-of-field compared with 10 percent of public school teachers. Similarly, about 37 percent of all vocational education teachers lacked an appropriate major or certification to teach vocational education. In contrast, 6 percent of all social science teachers, 9 percent of all English teachers, 10 percent of all science teachers, and 14 percent of all mathematics teachers were teaching out-of-field. Among public school teachers who taught in the middle school grades, 8 percent of social science teachers, 11 percent of English teachers, 13 percent of science teachers, and 18 percent of mathematics teachers were teaching out-of-field. However, among public high school teachers, 2 percent of social science teachers, 2 percent of English teachers, 3 percent of science teachers, and 5 percent of mathematics teachers were teaching out-of-field (Seastrom et al. 2002, pp. 55–56).¹⁰ The rates of out-of-field teaching by subject and level for private school teachers cannot be reliably calculated from SASS data because of the small sample sizes of private school teachers for each subject area.

⁴Both teachers who taught prekindergarten and teacher aides were excluded from this analysis. The categories “elementary schools” and “secondary schools” included all levels of schools, both graded and ungraded. (back to text)

⁵The remaining 2 percent of teachers were administrators (principals, assistant principals, etc.), librarians, or other support staff (counselors, social workers, etc.) who taught classes. These percentages do not sum to 100 because of rounding. (back to text)

⁶The category “public schools” throughout this analysis means all public schools—both traditional and charter public schools. (back to text)

⁷The elementary grades are K–4, but teachers who taught grades 5–9 were classified as teaching in the “elementary grades” if they identified themselves as elementary or special education teachers. The middle grades are grades 5–8, but teachers who teach a combination of grades K–9 were classified as teaching in the “middle grades” if (1) they have a main assignment field other than elementary education or special education, and (2) they do not teach any grade higher than grade 9. High school teachers either teach only 9th-grade students or teach students in any of the grades 9–12. Prekindergarten teachers were excluded from this special analysis. Ungraded teachers are included in totals but not in distributions by grade level taught. (back to text)

⁸Throughout this analysis, the phrase “all elementary, middle, and high school teachers” means all K–12 public and private school teachers regardless of whether they taught in a graded or ungraded school; in an elementary, middle, or high school; or in a combined school. (back to text)

⁹There are various ways to measure out-of-field teaching. In Seastrom et al. (2002), NCES reports four measures. The percentages of out-of-field teachers reported here—based on whether a teacher had neither a major nor certification in the main assignment field—yield the lowest estimates of these four measures because this measure ignores the cases where teachers have some classes that are outside their main assignment areas. Percentages of out-of-field teachers based on all classes taught tend to produce the highest estimates of these four measures because this measure gives equal weight to all teachers with any out-of-field classes, regardless of the number of classes. Measures based on the number of classes taught and based on the number of students taught usually fall in between these two teacher-based measures. For more details, see Seastrom et al. (2002), pp. 21–23. (back to text)

¹⁰The percentage of teachers who are teaching out-of-field also varied by school poverty concentrations and by minority enrollment. See U.S. Department of Education 2004, indicator 24. (back to text)