Of all the things schools can give students to help them succeed, effective teachers are the best bet. In education research, having an effective teacher consistently rises to the top as the most important factor in learning—more so than student ethnicity or family income, school attended, or class size (Center for Public Education 2005).
We know this because we can see the effects of good teachers from data tools like Tennessee’s value-added scores. When an effective teacher is in the classroom, scores rise and the positive impact can be dramatic, especially for poor and minority children.
Unfortunately, we don’t know exactly what it is that makes a teacher effective. Any single indicator of teacher quality—for instance, something like years of experience—rarely yields a strong correlation with improved student achievement. And, by any characteristic we can measure, teacher quality has not been equitably distributed across the nation’s schools. Schools that serve large proportions of low-income and/or minority students tend to have trouble attracting and keeping good teachers—a situation that seriously hampers their efforts to narrow achievement gaps.
In 2001, Congress, for the first time, took aim at teacher quality and sought to raise it, particularly in schools serving low-income students. Through its “highly qualified teacher (HQT)” provisions, the federal No Child Left Behind Act (NCLB) required all teachers to have at least a bachelor’s degree, to have full state certification, and to demonstrate knowledge of the subject matter they teach. The goal was to ensure that the children of poor families had the same access to good teachers as other students.
Eight years later, the record of that provision is mixed. The overwhelming majority of teachers have met the law’s definition of “highly qualified,” yet there is little evidence that teacher quality has improved markedly. While these characteristics defined base-level requirements, they did not ensure that qualified teachers were effective in the classroom.
As Congress gears up to reauthorize the Elementary and Secondary Education Act, there is a broad consensus that the new law should address some of the loopholes NCLB created and focus on ensuring that teachers are effective, not simply qualified. However, this issue is not so easily solved.
To try and get to the heart of the matter, we examined the evidence on teacher quality for this report and explored these questions: What are the characteristics associated with effectiveness? Are effective teachers distributed fairly across schools? How can those involved in school policy guarantee that all students get access to good teachers?
Three findings emerged:
- There is mixed evidence whether the factors commonly associated with teacher quality actually indicate whether teachers are effective in the classroom. In particular, taken alone, each of the criteria for “highly qualified teacher” status under NCLB is only weakly associated with effectiveness. Research has shown that teachers without these qualities are ineffective. But there is little evidence that meeting HQT standards alone means that teachers are likely to be “highly effective,” producing the gains needed to narrow gaps.
- No single teacher characteristic stands out as a must-have quality for effective teaching. However, some characteristics are more closely related to student achievement than others. For this reason, districts and schools should look at multiple criteria when hiring and assigning teachers.
- There are clear differences between schools based on the percentage of teachers who possess the characteristics associated with effectiveness. Schools with high enrollments of low-income and/or minority youth tend to have fewer effective teachers than others. This suggests that more needs to be done to reduce inequities in the distribution of effective teachers.
The following discussion expands on these results.
The challenge: Defining an effective teacher
Good teachers can be described in many ways. They can have strong credentials, teach top students, are creative, or are well-liked by students, parents, and their colleagues. All of these qualities have their merits. But most policymakers and school leaders would describe a “good” teacher as an effective one: someone who gets students to learn what they are expected to learn or more. If school administrators had tools for identifying who is most likely to succeed at this, they could make good decisions about recruitment, hiring, and assigning teachers.
In the late 1980s, economists and researchers developed methods for measuring the effect individual teachers have on their students’ learning separate from other factors that can influence achievement. These methods are statistically complex, but the basic premise is to compare the actual change in individual student achievement between the time students enter and depart a teacher’s classroom, independent from their prior performance. The calculation, then, represents the value added from being with that teacher (Hull 2008). Teachers who add value to student learning are said to be effective teachers.
In 2005, the Center for Public Education reviewed the most current teacher quality research available at that time. We reported that the value-added studies “provide empirical evidence that teachers make a substantial difference in student achievement. But they are silent on the question of what characterizes an ‘effective teacher.’” To answer that question, the Center looked at other research that lacked the empirical base of value-added studies, but nonetheless identified a positive relationship between specific teacher qualities and student performance. Many of these characteristics became part of NCLB highly qualified teacher requirements.
|NCLB’s “Highly qualified teachers”
The No Child Left Behind Act of 2001 (NCLB), the latest reauthorization of the Elementary and Secondary Education Act (ESEA), is the largest contributor of federal dollars to K-12 education to date and was intended to specifically address the educational needs of students from low-income families.
The teacher provisions under NCLB’s Title I require states to establish and implement plans that will place a “highly qualified teacher (HQT)” in every classroom in the core subjects.1 “Highly qualified” under NCLB means that teachers have at least a bachelor’s degree, have full state certification, and demonstrate “subject matter knowledge in each subject they teach.” States are given some flexibility to define specific approaches to meeting these criteria, particularly in regard to how teachers demonstrate subject matter knowledge.
States are held accountable under the law for making sure all teachers meet the HQT standards. States must also ensure that low-income students and minority students are not taught by inexperienced, out-of-field, or teachers not “highly qualified” at higher rates than other student groups (U.S. Department of Education 2007).
As of the 2006–2007 academic year, 94 percent of classrooms in the United States were being taught by teachers meeting HQT standards. This represents a 7 percentage point increase over the 2003–2004 school year, the first year schools had to report on HQT status (U.S. Department of Education 2008). However, gaps in the availability of highly qualified teachers, although small, were still present between high- and low-poverty schools. (See Figure 1 .)
Survey data also reveal differences in the percentage of highly qualified teachers based on schools’ NCLB status. Schools that meet adequate yearly progress (AYP)—the NCLB targets for student achievement—are most likely to also have teachers who meet HQT standards. Figure 2 shows a clear relationship between schools that do not meet AYP goals and the presence of teachers who likewise do not meet HQT standards. Schools in restructuring have the fewest highly qualified teachers. These schools have failed to make AYP for four consecutive years.
These patterns suggest that HQT provisions may be identifying inequities in educational resources that affect student achievement. But is closing the HQT gap sufficient to close the achievement gap between groups of students? When NCLB was enacted, research was clear that the absence of HQT qualifications indicated an ineffective teacher, but it wasn’t clear whether the presence of those same qualifications guaranteed an effective teacher. What further discoveries has research made about the qualities that indicate an effective teacher in the years since NCLB was enacted?
Current research does indeed illuminate whether some individual characteristics indicate teacher effectiveness.
State certification: Some types
All states require some form of licensure and require teachers to earn certification in order to earn a full teaching position. Yet many states have also allowed districts to hire uncertified teachers on an emergency basis if they were unable to fulfill staffing needs. NCLB required teachers to be certified in order to be designated as “highly qualified”; however, the statute left the definition of “certified” to states to decide, and it allowed both traditional and alternative routes.
Traditional certification: Yes, especially in a subject. Traditional teacher certification typically requires candidates to successfully complete a university-based teacher preparation program that meets state specifications and pass a licensure examination, such as the nationally administered Praxis. (Teachers typically must undergo a criminal background check as well.) Research suggests that traditional certification might matter.
Simply having traditional certification is good, but certification in the particular subject being taught often has a stronger correlation with student success. Studies have found that subject-area certification in mathematics for secondary teachers is associated with higher student performance in the subject (Goe 2007, Clotfelter et al. 2007). Another study in San Diego also found that certified math teachers had more impact on student achievement than a teacher without math certification at the middle school and high school level (Betts, Zau, and Rice 2003). As for English courses, at the high school level students are better off being taught by a teacher who is certified in English than if they were taught by a teacher certified in an unrelated field (Clotfelder et al. 2007b). Some research has found similar results in social studies (Dee and Cohodes 2005).
At the elementary level, the findings are often mixed, with some studies showing little or no difference on elementary students’ performance (Gordon et al. 2006).
Alternative certification: Mixed. Alternative routes to certification allow aspiring teachers to bypass traditional university teacher preparation programs to qualify for entry to the profession. Researchers have documented at least 140 different alternative certification programs throughout the United States (Glass 2008). Not surprisingly, evidence on these programs’ effectiveness is mixed, making it impossible to make an across-the-board statement about alternate routes per se. The most visible of these programs, Teach for America (TFA), has prompted the most attention from policymakers and researchers. TFA recruits recent college graduates from top colleges who exhibit leadership capabilities to teach for at least two years in high-needs schools. In 2005, the Center reported that the jury was still out on TFA’s effectiveness, based on the conflicting results of two studies. Newer studies, however, come down more firmly on the TFA side of the ledger. For example, in a national study, Glazerman, Mayer, and Decker (2006) found that TFA teachers in elementary schools had a positive impact on students’ math achievement, although they found little effect in reading. In their study of TFA teachers in North Carolina high schools, Xu, Hannaway, and Taylor (2007) determined that TFA teachers were more effective teachers of math, science, and English than the teachers who would have otherwise taught those students. The authors wrote: “Other things being equal, the findings suggest that disadvantaged students taught by TFA teachers are better off than they would be in the absence of TFA” (Xu, Hannaway, and Taylor 2007)
While the specific reason has not been firmly established by research, Teach for America’s recruitment from highly selective colleges seems to benefit students. (See the section on Academic Qualifications. For a further discussion of TFA, see the Center’s “Wanted: Good teachers” report.)
Emergency certification or lack of certification: Negative impact. The research is clear on one aspect of teacher certification: Putting teachers who have emergency or no teaching credentials in classrooms is not likely to produce good results. Such teachers have been shown, on average, to have a negative effect on student achievement (Goe 2007, Darling-Hammond et al. 2005).
National Board Certification: To some extent. The National Board for Professional Teaching Standards has developed rigorous assessments of teachers’ knowledge and skills and certified those who demonstrated high abilities. To date, about 74,000 veteran teachers (those who have taught for at least five years) have become certified by the National Board. An extensive review of the literature on the program found that, overall, students taught by National Board Certified teachers score higher on standardized tests of reading and mathematics than do comparable students taught by teachers who are not Board certified. However, the effects, while significant, were not uniformly large. (National Research Council 2008).
Subject-Matter Knowledge: Yes
It seems intuitive that teachers need to be well-versed in the subjects they teach, and NCLB’s HQT provisions require teachers to demonstrate
subject-matter knowledge in order to earn highly qualified status. However, large numbers of teachers lack a major in their main field of assignment, including 24 percent of high school math teachers and 16 percent of high school social studies teachers (NCES 2008).
The Key Characteristics
When looking for a qualified teacher, look for a combination of these characteristics:
- High SAT or other college entrance scores
- A degree from a selective, rigorous college
- High scores on the Praxis, or other licensing exam
- More than four years of experience
- Strong subject-matter knowledge
As with hiring uncertified teachers, the assignment of teachers to subjects in which they lack a college major usually stems from emergency staffing needs. Schools that lack enough teachers to staff five math classes might assign a science teacher to one class, for example.
As the Center’s original report on teacher quality found, most studies before 2005 found that teacher subject-matter knowledge was correlated to higher student achievement. However, current research is more effective at measuring a teacher’s impact on the change in student achievement, which has led to more mixed results. A breakdown of how that knowledge was demonstrated and how it affects student achievement will provide a clearer picture of the impact of subject-matter knowledge on student achievement.
A teacher can demonstrate subject-matter knowledge in several ways:
- A teaching credential in a subject
- A major or minor in a subject in college
- An advanced degree in a subject
- Demonstrating knowledge on a test
As discussed earlier, teachers with a specific credential in the subject are more closely associated with student success.
A major or minor in the subject. Not surprisingly, students who had math teachers with a bachelor’s degree in math earned higher math scores (Goldhaber and Brewer 2000, Dee and Cohodes 2005). Some research has also found this to be the case in science (Goldhaber and Brewer 2000) and social studies (Dee and Cohodes 2005). While one recent study of Chicago Public Schools found no relationship between having a degree in a subject area and student achievement in that subject, the study was constructed differently (Aaronson, Barrow, and Sander 2007).
An advanced degree in the subject. In addition to a bachelor’s degree, earning an advanced degree in a subject is an indicator of even higher subject-matter knowledge. Once again, the impact is primarily felt at the middle or high school levels. In North Carolina, across all subjects, students who were taught by a teacher with a master’s degree in the subject were better off than their classmates who were taught by a teacher with just a bachelor’s degree (Clotfelder et al. 2007b).
Other studies only found this effect in specific subjects. Goldhaber and Drewer (2000) found that students whose teachers held a master’s degree in math had higher math achievement than students whose teachers did not. In San Diego, students were only better off in reading when taught by a teacher with a master’s degree or Ph.D. (Betts, Zau, and Rice 2003).
Test scores. Unlike the other three indicators of subject-matter knowledge, teachers with higher test scores are more effective at both the elementary and high school levels. At the elementary level in North Carolina, students who were taught by teachers who scored higher on the math section of the state’s licensure exam made more academic gains in math than students taught by teachers who scored lower (Clotfelder et al. 2007a).The same was true for reading. Even at the elementary level, teachers in New York City who scored higher on the SAT math section were more effective than teachers who scored lower (Boyd et al. 2007).
In all of these studies, no one method of demonstrating subject-matter knowledge showed consistent effects for all students across all subjects. However, when taken together all signs point to the importance of a teacher having an in-depth knowledge of the subject matter being taught, especially at the high school level.
Advanced degrees in general: No
Having an advanced degree in the subject a teacher is teaching can have a positive impact on student achievement, especially at the high school level. But what about at the elementary level where teachers don’t typically teach a certain subject? What about teachers who have an advanced degree in a field unrelated to the subject they are teaching? Does merely having an advanced degree improve teacher effectiveness?
Most district policies and collective-bargaining agreements assume the answer is yes. A teacher with any advanced degree earns a significant salary boost. Nationally, 2.1 percent of school expenditures—$174 per pupil—are attributed to increases for master’s degrees, and the expenditures are considerably higher in some states (Roza and Miller 2009).
However, recent studies have produced evidence that advanced degrees are not associated with higher levels of teacher effectiveness. Using an extensive database from Florida, Harris and Sass (2007) found that simply having any sort of advanced degree (as opposed to studies that looked at advanced degrees in the subject matter being taught, as discussed above) did not contribute to teachers’ effectiveness at any level, except for middle school math. Moreover, Clotfelter, Ladd, and Vigdor (2006) found a consistently negative effect of a master’s degree on student achievement in a study of 4,000 elementary school teachers in North Carolina. Likewise, an analysis of the Texas School Project data found little to no evidence that merely having a master’s degree improved teacher skills or raised the quality of instruction at the elementary school level (Rivkin, Hanushek, and Kain, 2005).
Academic Qualifications: Yes
Teaching has a reputation as a profession that attracts the least academically qualified individuals. College freshmen who say they intend to go into teaching have among the lowest SAT scores of any group. However, those who actually pursue teaching degrees and take state licensure tests have verbal SAT scores above the national average, and the average SAT scores of prospective teachers have increased over the past decade. Nevertheless, teachers’ math SAT scores are below average, and scores for those pursuing elementary education, physical education, and special education are well below average (Gitomer 2007). Some efforts to raise quality, such as Teach for America, are aimed at enticing more academically qualified students to teaching.
There is evidence that teachers’ academic qualifications are associated with effectiveness. Students whose teachers have higher math SAT scores have higher math achievement; so, too, do students whose teachers attended a more competitive college, although less so (Boyd et al. 2007). Higher scores on teacher licensing tests are also associated with higher levels of student achievement, particularly in math (Clotfelter, Ladd, and Wigdor 2007).
Seniority: More than four years
As with any profession, teachers benefit from experience. Most districts recognize the value of experience by paying teachers based on the number of years they have taught, both to reward their knowledge and to retain them in their jobs.
The evidence shows, though, that experience matters only up to a point. Studies have found that first-year teachers produce gains in student achievement that are substantially smaller than those produced by teachers with ten to fifteen years’ experience. However, most of the gains from experience occur in the first four years of teaching (Rockoff 2004; Rivkin, Hanushek, and Kain 2005; Kane, Rockoff, and Staiger 2006). It is unclear whether this plateau effect reflects the possibility that experience yields little benefit after the first few years, or that the more able teachers leave the profession after that time, leaving the weaker teachers in the classroom.
Effective teachers and equity
An effective teacher is a valuable commodity. The positive impact a good teacher has on learning can be dramatic, especially for poor and minority children. Making sure all students have access to effective teachers, then, is just as crucial as providing the effective teachers in the first place. Although we can’t evaluate whether there is equitable distribution for all the characteristics discussed in this paper, we do know about it in these particular characteristics:
Certification. Although the NCLB HQT provisions have likely led to a reduction in the number of uncertified teachers, many districts facing shortages continue to hire teachers who lack certification, at least temporarily. As might be expected, low-income and minority students are more likely to have an uncertified teacher than their more advantaged peers. Esch and colleagues (2005) found that 20 percent of teachers in California schools serving 91 to 100 percent minority students were not fully certified, compared to 11 percent in schools serving few or no minority students. They also found disparities in schools with large ELL student populations (i.e., 40 percent or more of the student body) where 18 percent of the teachers were not fully certified; by contrast, schools with small ELL student populations (6 percent or less) had fewer teachers (13 percent) who were not fully certified (Esch et al. 2005). Finally, National Board-certified teachers tend to disproportionately teach more advantaged students, and there is little evidence that the program has had the “spillover effect” of improving the quality of teachers throughout the system (National Research Council 2008).
Subject-matter knowledge. The use of out-of-field teachers is considerably more widespread in schools that serve low-income and minority students. In high-poverty schools, 41 percent of mathematics classes were taught by out-of-field teachers, compared with 17 percent of low-poverty schools. African American and Latino students are twice as likely as white students to be taught by out-of-field teachers; 30 percent of minority mathematics classes are taught by teachers who lacked an academic major and certification in the subject, compared with 15 percent of classes with white students (Education Trust 2008). NCLB reports have also found that the percentage of highly qualified secondary teachers with a degree in the subject they teach varies by subject area and school characteristics (See Figure 4 ),
Academic qualifications. As with other measures, teachers’ academic qualifications are not distributed evenly among schools. Low-income and minority students are less likely than their more advantaged peers to have teachers with higher academic credentials. In New York City, for example, 35 percent of teachers in high-poverty schools had failed the state licensure exam on their first try, compared with 15 percent in the low-poverty schools (Boyd et al. 2007). However, the gap narrowed between 2000 and 2005.
Seniority. There is considerable evidence that novice teachers, who are less effective than their more experienced peers, are much more likely to teach low-income and minority students. In one study of New York City elementary schools, for example, non-white children were 50 percent more likely than white children to have a teacher with no prior experience, although the gap narrowed slightly by 2005 (Boyd et al. 2007). NCLB also reports that the percentage of highly qualified teachers with fewer than three years of experience varies by school AYP status and SES of student population, with poor, high-minority, and non-AYP schools having more novice teachers. (See Figure 3 ).
Implications for districts and federal policy: Pursue a combination of characteristics
The research makes clear that some characteristics are more likely than others to be associated with effectiveness, but no one factor trumps all the others. However, a study of teachers in New York City suggests a combination of characteristics makes a substantial difference. The study found that teachers in high-poverty schools in 2005 were more likely to be certified and to have stronger academic qualifications than teachers in those same schools four years earlier. (that is, the 2005 teachers had higher SAT scores, they attended more selective colleges, and they were more likely to have passed the state licensure examination—such as the Praxis exam—on the first try).
The study also found that these teachers were more effective in the classroom, reducing the achievement gap between low- and high-poverty students by almost a fourth. The authors conclude: “The performance of students in 4th and 5th grade math can be substantially increased across all stratifications of students by recruiting and hiring better qualified teachers” (Boyd et al. 2007, p. 16, emphasis in original).
Boyd et al. (2007) also point out that the narrowing of the achievement gap in New York City resulted from a policy decision by the district to recruit teachers with stronger credentials and place them in high-poverty schools. Districts seeking to raise achievement should consider seeking teachers with observable characteristics that are associated with effectiveness, such as certification, academic credentials, and experience.
In addition, their study suggests that the conscious decision by New York to place teachers who were likely to be effective into schools with low-income and minority students narrowed the city’s teacher-quality gap substantially. This finding suggests that districts and federal policy can close gaps by explicitly placing their high-quality teachers in schools serving low-income and minority students.
Similarly, federal policymakers should also examine the research on the characteristics associated with teacher effectiveness in determining which teachers can earn “highly qualified” status. And, as Gordon, Kane, and Staiger (2006) suggest, measures of student achievement can also show which teachers are effective on the job and can supplement information about qualifications.
Questions for school board members
1. What is the current distribution of teachers who have the characteristics most associated with effectiveness?
2. How can we attract more teachers with higher academic qualifications?
3. How can we retain teachers who have more than four years of experience?
4. What is our current rate of certification? What are we doing to reduce emergency certification?
5. Would we consider a policy of placing best-qualified teachers in schools with a majority of low-income or minority students?
6. Do we have the data tools in place to measure teachers’ effectiveness with students?
7. Do we currently pay more for advanced degrees? Should we continue this practice? If so, how do we align this practice with research on effective teachers?
1 NCLB defines core subjects as English, reading or language arts, mathematics, science, foreign languages, civics and government, economics, arts, history, and geography.
This article was written by Robert Rothman, senior fellow at the Alliance for Education Excellence, with Patte Barth, director of the Center for Public Education. The article is based, in part, on a research review conducted for the Center by Edvantia, Inc.
©2009 Center for Public Education