Unformatted text preview: Journal of Economic Perspectives--Volume 24, Number 3--Summer 2010--Pages 133150 The Quality and Distribution of Teachers under the No Child Left Behind Act
Eric A. Hanushek and Steven G. Rivkin T he heart of accountability under the No Child Left Behind (NCLB) Act is an attempt to change the existing incentives in schools with the ultimate objective that all students meet a proficiency standard. Existing research indicates that nothing is more important to high achievement as having effective teachers, implying that the impact of new incentives on teachers will be central to any consideration of the accountability statutes. Tracing the impacts of NCLB on the stock and distribution of teachers is, nonetheless, a difficult and uncertain task. The belief that the quality of teachers matters a great deal to the quality of education received by students has actually proven hard to substantiate, and the reasons for this difficulty are key to assessing the impacts of No Child Left Behind. A substantial body of research going back to the Coleman et al. (1966) report has attempted to link commonly used measures of teacher quality--such as experience, degree level, and state teacher certification--to student outcomes. Surprisingly, except for perhaps the first few years of classroom experience, no robust connection has appeared; for example, Hanushek and Rivkin (2006) review various studies attempting to identify characteristics of effective teachers. One Eric A. Hanushek is Paul and Jean Hanna Senior Fellow, Hoover Institution, Stanford University, Stanford, California. Steven G. Rivkin is Rachel and Michael Deutch Professor of Economics, Amherst College, Amherst, Massachusetts. Hanushek is Chairman of the Executive Committee and Rivkin is Associate Director of Research, Texas Schools Project, University of Texas at Dallas, Dallas, Texas. Both authors are Research Associates, National Bureau of Economic Research, Cambridge, Massachusetts. Their e-mail addresses are [email protected] stanford.edu stanford.edu and [email protected] [email protected] doi=10.1257/jep.24.3.133 134 Journal of Economic Perspectives common interpretation of these findings was that the seemingly obvious wisdom was incorrect and that, while student outcomes clearly exhibited considerable variation, little of it was due to teachers. More recent research has, however, produced very different results. This research, based on newly available administrative data bases, measures teacher quality on the basis of student achievement gains and finds very strong effects of better teachers.1 A good teacher is somebody who regularly produces high average learning gains in a class, while a bad teacher regularly produces low gains. Such analyses of teacher effectiveness, or teacher value-added, have produced remarkably consistent estimates of the variation in teacher quality (Hanushek and Rivkin, 2010b). A one-standard-deviation improvement in teacher effectiveness (going from the average teacher to one at the 84th percentile) would move the average student from the 50th to the 56th percentile in the year with the better teacher. At the same time, these variations in quality have not been closely related to measurable characteristics of the teacher--making this analysis consistent with the prior research. In practice, schools use a range of information to evaluate teachers including administrator observations and parental feedback, and the testing associated with school accountability can be used to measure teacher productivity on the basis of the contribution to raising achievement. The main effects of No Child Left Behind on the quality of teaching are likely to come through two provisions of the act. First, NCLB establishes benchmarks based on test score pass rates that schools must meet in order to remain in good standing and avoid sanctions. Since teachers are central to student performance, this accountability component of NCLB is likely to have direct effects on both the demand for and supply of teachers and therefore on both the composition of the stock of public school teachers and the distribution of those teachers among schools. Second, NCLB explicitly requires districts to have "highly qualified" teachers, and the enunciation and enforcement of such a standard might have an additional effect on the composition of teachers. In this paper, we will discuss three avenues by which these requirements might affect the quality of teachers.2 First, we will argue that the requirements for "highly qualified" teachers are unlikely to have had any perceptible effect on the performance of students. Second, the combination of quality requirements and the 1 While this research began several decades ago using specialized datasets (for example, Hanushek, 1971; Murnane, 1975; Armor et al., 1976; Hanushek, 1992), the recent analyses have relied more upon administrative data bases that are generally linked to the development of state or local accountability systems (for example, Sanders and Horn, 1994 [Tennessee]; Rivkin, Hanushek, and Kain, 2005 [Texas]; Aaronson, Barrow, and Sander, 2007 [Chicago]; Kane, Rockoff, and Staiger, 2008 [New York City]; and Boyd, Grossman, Lankford, Loeb, and Wyckoff, 2006 [New York City]). 2 Most of the discussion throughout this paper actually applies also to principals and other school administrators. The research on these, however, is extremely limited, and we confine our discussion just to teachers. Eric A. Hanushek and Steven G. Rivkin 135 more-stringent testing environment could make teaching appear more costly and risky as a profession and thus alter the composition of new entrants, but at least so far, we find no evidence of such effects. Finally, the accountability provisions might change the dynamics of the labor market for teachers, including decisions about hiring and job separation. While not completely understood, this channel might be quite important, especially at low-performing schools where the stress of the accountability requirements is highest. We will provide new evidence from Texas on the relationship between school accountability ratings and teacher transitions both out of schools and out of grades three through eight, the grades subject to NCLB testing requirements. Finally, we offer some observations about potential policy implications and a future research agenda. Drawing conclusions about the effect of the No Child Left Behind legislation on teacher labor markets is not straightforward. NCLB actually represented a continuation of an already powerful movement toward test-based accountability for schools that began almost two decades before its passage. Thus, some of the relevant evidence about the effect of teacher quality requirements and testing requirements comes not from NCLB per se, but from its precursors across different states. For example, Texas had a fairly strong accountability system beginning in 1993, and indeed the underlying principles helped guide the development of NCLB by President George W. Bush, who of course had formerly been the governor of Texas. Teacher Quality Requirements
The No Child Left Behind act contains a somewhat anachronistic set of requirements related to teacher quality. Instead of just relying on accountability based on student performance, which implicitly introduces incentives for hiring and retaining high-quality teachers, NCLB adds a direct requirement that all schools have "highly qualified teachers." The definition of a highly qualified teacher was left up to the individual states, but the focus was almost exclusively on teacher characteristics, like certification or degree level, which have not been shown to have a strong relationship to student outputs. Moreover, states have commonly defined "quality" in such a way that the requirements create no additional burden on either existing teachers or new entrants. Prior to NCLB, new teachers were typically required to have a bachelor's degree, to be fully certified, and to demonstrate subject matter knowledge, generally through tests. Under NCLB, existing teachers including those with tenure were also supposed to meet standards. They could meet the same requirements that were set for new teachers or could meet a state-determined "high, objective, uniform state standard of evaluation," also known as HOUSSE. The idea was clearly to upgrade the teaching force. Yet, there is little evidence that the state chosen standards were very binding (Moe, 2005). Few states showed any interest in any major changes in the terms of employment for existing teachers, 136 Journal of Economic Perspectives leading them generally to opt for definitions consistent with their existing licensing and certification standards for teachers.3 The teacher quality requirements of the No Child Left Behind legislation have received little research attention, in part because state rules require few changes from pre-existing practice. There is little evidence that the rules have altered the trend lines in the observable traits of teachers. Moreover, as noted earlier, there is little evidence that, even if the observable traits were increased, it would improve student performance. For example, requiring teachers to obtain a master's degree to be fully certified does not, by existing research on student outcomes, improve the quality of instruction. All in all, these direct provisions are unlikely to have had much effect either on the teaching profession or on student achievement. Risk and Changes in Teacher Quality
Many education researchers and policymakers point to high turnover of teachers during the first few years of teaching as one of the main impediments to raising school quality, often without recognizing that early exit rates from teaching mirror those in nonteaching occupations (Stinebrickner, 2002; Ballou and Podgursky, 2002).4 Historically, after the initial period of career sampling, a job in the teaching profession has been stable and low-risk. To be sure, certain schools in high-poverty communities often had high turnover of teachers, but those teachers were typically moving to other schools, not leaving the profession (Hanushek, Kain, and Rivkin, 2004). Teacher tenure provisions are generally governed by state law, and tenure is often granted quickly. Forty-three states have a probationary period before tenure, of three or fewer years (National Council on Teacher Quality, 2008). Once in a teaching position, one's salary is determined almost exclusively by years of experience and graduate degrees (along with any contract renegotiation about overall level of salaries). The work schedule roughly follows the school schedule and calendar. This kind of stable and well-defined job will always be desirable to some of those making occupational choice decisions (for discussion, see Stinebrickner, 2001, who emphasizes family considerations by teachers). Increased accountability could alter some of these characteristics, which in turn could effect the composition of teachers. For example, if accountability led to a closer link between compensation and employment on the one hand and student outcomes on the other, the risk of a teaching job would increase. How this would HOUSSE requirements in the each of the states have been compiled by the Education Commission of the States at http://www.ecs.org/ecsmain.asp?page=/html/educationissues/teachingquality /nclb-hqtp/db_intro.asp (accessed April 13, 2010). Searching the 50 state databases reveals that only a handful of states even mention student achievement as a way of demonstrating being highly qualified. Teaching experience and prior academic coursework are the most common features, although teachers generally have alternative ways to demonstrate their qualifications. 4 Indeed, of the new entrants in 2000, a greater number were returning teachers than either new graduates or delayed entry graduates (Provasnik and Dorfman, 2005). 3 The Quality and Distribution of Teachers under the No Child Left Behind Act 137 affect the composition of teachers depends on a number of factors. For example, if less-effective teachers were made more vulnerable, while more-effective teachers would typically benefit, the profession might attract a different set of entrants. Alternatively, those who are potentially the best teachers, when weighing a lifetime commitment to teaching, could steer away if they felt the risk of being judged unfairly was too high. At this point we know very little about how accountability affects risk or even the perceptions of risk and thus its effect on the willingness to enter or remain in teaching. The absence of evidence on the link between accountability and the composition of teachers is not surprising given that prior research has found it difficult to say much about how any characteristic of the teaching occupation affects the composition of teachers. For example, the pay of teachers, particularly female teachers, fell dramatically relative to earnings of nonteacher college graduates for the last half century (Hanushek and Rivkin, 2006). In 1950, the average young women teacher earned more than 55 percent of young women with a college degree; by 2000, this ratio had fallen to 35 percent. School districts seem generally slow in adjusting to demand, particularly on the salary side. The salaries of teachers have not kept up with those on the outside, so over time (as noted above) teachers have been drawn from lower down in the salary distribution.5 Along with this, there is substantial evidence of commensurate declines in teacher test scores. For example, Bacolod (2007) finds the 41 percent of teachers born 194145 had IQ scores in the top quintile, but only 19 percent of those born 196364 were drawn from that high in the distribution.6 However, there is little or no evidence of direct links between these changes and decreases in teacher effectiveness as measured by student outcomes.7 A clear impediment to drawing inferences about the effects of changes in salary, risk, or other factors on the composition of teachers is the dependence of any effects on district behavior during the hiring process. In contrast to competitive markets where the assumption of profit maximization justifies the assumption that firms will hire the most qualified workers at the chosen wage, public schools do not pursue a single objective and often face little competition for students. If schools pursue alternative objectives to high instructional quality,
Some interpret this as reflecting "Baumol's disease." A low-productivity sector faces increases in real production costs due to a more rapid increase in wages than in productivity. This cost pressure on the low-productivity sector (think schools) could lead to a decline in salaries (and thus quality) if budgets do not keep up with wage growth (Baumol and Bowen, 1965; Baumol, 1967). However, this interpretation is inconsistent with the fact that schools have systematically reduced class sizes and pupilteacher ratios over the same period where relative wages are declining. In other words, schools have substituted toward more of the expensive resource. 6 Corcoran, Evans, and Schwab (2004a, 2004b) similarly find that, while mean performance on achievement tests of teachers did not change much between 19642000, the proportion of teachers in the top deciles fell significantly. 7 While teacher test scores tend to be related to student achievement more reliably than other measures, the relationship found across existing studies remains quite weak (Hanushek, 2003). Similarly, teacher salaries have not been closely linked to student performance, although most of the evidence comes from cross-sectional studies that do not give a good indication of what might happen with substantial changes in the overall level of salaries.
5 138 Journal of Economic Perspectives such as favoritism toward friends, family, or politically well-connected applicants, the effects of changes in compensation are likely to be muted. It should be noted there is suggestive evidence that more competition among public school districts (as measured by the number of districts in a metropolitan area) raises the quality of teachers (Hanushek and Rivkin, 2003), consistent with the view that a lack of competition leads administrators to pursue objectives other than maximizing the quality of education. Moreover, the institutional structure including tenure and extensive unionization appears to have led to far less variation in salary than would be expected in competitive markets. For example, the absence of sizeable compensation differences by subject or working conditions appears to have introduced substantial variation in the supply of teachers by subject and school characteristics. Overall, the supply of people training for teaching exceeds by a considerable margin the number of positions that annually become open in schools. For example, in 2000, 86,000 recent graduates entered into teaching, even though 107,000 graduated with an education degree the year before (Provasnik and Dorfman, 2005; U.S. Department of Education, 2009).8 Yet there are persistent shortages of mathematics, science, and special education teachers as well as shortages of certified teachers willing to work in high-poverty schools, leading to the employment of many teachers who lack certification or training in a given area. The observed distribution of teachers is an outcome reflecting those who train and apply for teaching jobs and those who are selected by school systems. At this point we know little about the effects of NCLB on either the distribution of teacher quality or the separate effects on demand or supply. There is limited evidence of the accountability effects on turnover and the distributions of teacher characteristics among schools and grades, findings we discuss in the next section. At a minimum, it appears that the supply of graduates with education degrees changes little with the introduction of state accountability and NCLB. Existing Evidence on Teacher Dynamics
The high-stakes accountability pressures of No Child Left Behind would be expected to alter the decision-making processes of both teachers and administrators and thus the equilibrium distribution of teachers among grades, schools, and districts.9 Such changes could affect the distribution of teacher quality through Note that the recently graduated group entering teaching also includes a number of people who graduate with degrees other than in education, making the excess supply of education graduates even larger. Similar differentials existed throughout the 1990s, implying that the stock of trained teachers not in the teaching profession is substantial. 9 We characterize accountability as increasing the stakes for teachers (and administrators). At the same time, contract provisions, particularly for teacher tenure, put some limits on this. We presume nonetheless that administrators can put extra pressure on teachers with the advent of student testing and accountability. 8 Eric A. Hanushek and Steven G. Rivkin 139 several channels: 1) increasing turnover and thus the share of teachers with little or no prior experience; and 2) changing the distribution of quality conditional on experience. Rookie teachers on average take some time to learn the skills of classroom management, to develop good lesson plans, to know how best to convey knowledge, and the like.10 Because schools serving disadvantaged populations are harder to staff, they have higher teacher turnover and are likely to have more rookie teachers and more difficulty attracting experienced teachers. Given the paucity of evidence on NCLB effects on teacher labor market dynamics, we begin this section with evidence on the pre-NCLB period. First, we describe the pattern of teacher transitions by salary and student characteristics presumed to be correlated with working ...
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