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Improving State Need Assessments of Secondary Science and Mathematics Teachers: Challenges, Possibilities, and Recommendations

Michael B. Allen
March 2010


Explaining Current Need

Does a state currently have a need1 for additional teachers to staff classes in science and mathematics? The answer to this question reflects the adequacy of the state’s supply of science and mathematics teachers to meet the state’s teacher demand. A satisfactory answer, however, addresses not only the extent to which the aggregate supply statewide meets the aggregate demand, but also the extent to which individual schools and districts throughout the state are able to staff the science and mathematics classes they offer with individuals who are adequately qualified to teach them.

It is the precisely the purpose of Establishing a State’s Current Need for Science and Mathematics Teachers to provide guidance in developing the sort of thorough and reliable assessment that would make such a satisfactory answer possible. The focus of the discussion is on the need for teachers in a state’s public schools because it is a state’s or district’s direct responsibility to address the need for teachers in those schools. Certainly, at a time when there is an increasing dependence upon private schools – especially private charter schools – to provide educational services in a district, a need assessment of teachers in these schools also would be worthwhile to include private schools, as well. The focus here is also limited to secondary science and mathematics because the need for teachers at the secondary level is more acute and the related policy issues are distinct from those in elementary education.

The most straightforward approach to determining the extent of current teacher need involves obtaining several kinds of present-time information from individual schools and districts. The most fundamental information is the number of classes that are not staffed by adequately qualified teachers, but additional information that can reveal difficulties in hiring, recruiting, or retaining teachers is also important. What makes a teacher adequately qualified is vigorously debated, but possessing an appropriate state license2 to teach the science or mathematics classes to which a teacher is assigned should be the minimum criterion.

A few states have sophisticated teacher data systems that ensure a high degree of uniformity and completeness of data from throughout the state, but most states must still rely on local data sources that may not be completely reliable. For present-time estimates, states have no choice but to do the best they can with the data at their disposal. They may want to consider significantly upgrading their teacher data capacity in the future, not only to improve their ability to track their teacher workforce and better estimate teacher supply and demand but also to ensure a more powerful accountability system in line with federal recommendations.

Data Checklist

To construct an estimate of a state’s current need for science and mathematics teachers, the state should ideally have the following information at its disposal (with good confidence in its reliability), both for individual districts and for the state as a whole. The “Basic Data” are the minimum kinds of data required to develop a reliable first-order estimate of the state’s current unfilled need for teachers. The “Bonus Data” are data that, if available and reliable, will enable states to refine that first-order estimate. Clearly, states and districts ultimately must make a need determination with the best data available, even if it does not meet the ideal for quality or scope.

Basic Data:

  • The number of classes in science and mathematics that are not currently staffed by adequately qualified teachers – teachers who have demonstrated adequate knowledge of the subject they are teaching and who have either full teaching licenses or temporary licenses pending completion of a teacher preparation program in which they are currently enrolled
  • The number of classes in science and mathematics that had to be cancelled because schools and districts could not find adequately qualified individuals to teach them
  • The years of experience of science and mathematics teachers in each school in order to determine whether some schools have a disproportionately inexperienced faculty that could indicate difficulty in recruiting or retaining good teachers

Bonus Data:

  • The average rates of student and teacher attrition in science and mathematics during the school year – in order to account for any additional need for teachers during the year that might arise after the current need assessment is made
  • The relative difficulty local district administrators had in filling positions during the current and previous few years in science and mathematics (ideally expressed as the number of applicants per position, compared with the number of applicants for similar positions in other districts and the number of applicants for positions in other subjects)

The Context of Current Need Assessments

Current Need and Future Need

The starting point for states’ efforts to identify their need3 for teachers in science and mathematics – i.e., the shortfall or surplus4 of teachers that results from the interaction of teacher supply and demand – is their analysis of their current need situation. The current need assessment will reflect several important factors and assumptions that will be important and perhaps more explicit in calculations of future need, especially the appropriate class size or student-to-teacher ratio and the acceptable qualifications for teachers of specific science and mathematics subjects. In addition, the degree of rigor and precision employed in developing the estimate of current need, as well as the quality of the data used, can set the standard for the quality of estimates of future need.

The current need estimate also influences the actual calculations in future need projections to the extent that it (along with historical estimates) serves as the baseline for projections into the future. Current need can be no more than a baseline for future need, however, unless it can be confidently assumed that the demand for and supply of teachers will remain constant. Given the likelihood of changing student demographics, volatility in the overall economy and consequently in the teacher labor market, and a growing trend among states and districts to increase high school graduation requirements and ensure that high school graduates are college ready, such an assumption of constancy is not apt to be valid very far into the future in most states.

Methodologically, the sort of current need estimate proposed here is much simpler and should be much more reliable than estimates of future demand. The current need estimate is fundamentally descriptive and employs present-time data to determine whether there is a sufficient number of teachers to cover the demand for classes. These estimates involve no inferential statistics and no predictions or projections into the future, which always have a degree of uncertainty attached to them. Thus, the methodological concerns of the current need estimate are focused overwhelmingly on the quality and nature of the data collected, not on the validity and reliability of various forecasting or projection models. Nevertheless, even the most careful estimate of current need will provide only a good approximation of the actual need, whether at the local level or statewide. As will be clear from the ensuing discussion, there are simply some data points that are extremely elusive, especially those which involve difficult choices about the allocation of school resources or which inevitably rely on perceptions of the adequacy of the school curriculum or of the teachers delivering it.

Estimates and Responses

We can assume that a teacher shortfall is the result either of an actual shortage of supply (there are simply not enough teachers to go around) or of the competitive disadvantages of certain states, districts, or schools in the teacher labor market (e.g., inadequate recruitment efforts, unattractive compensation policies, problematic hiring practices, or high opportunity costs such as geographic isolation or challenging working conditions). It would be helpful for a particular state, district, or school to know the exact reasons for any current shortfall they may be facing in order to best target efforts to respond. Beyond the calculation of teacher need, successful efforts to address any need identified – especially over the longer term – require a solid grasp of the teacher supply side of the picture in order to select appropriate strategies. And an adequate view of the teacher supply picture involves not just a current snapshot but historical data that provide a longitudinal look at the relevant patterns and trends, as well as an understanding of relevant economic factors and their impact. Guidance in developing estimates of a state’s teacher supply is provided in a separate component of this project, Projecting a State’s Future Need for Science and Mathematics Teachers, because calculating supply plays a more essential role there.

Realistically, however, the repertoire of possible responses to an immediate shortage situation is limited. There is only a very limited range of actions a state or district can undertake to address a current shortfall of teachers because what’s required in response are very immediate “fixes,” which cannot await the lengthy deliberations of the policy-making process. Responses to immediate needs for teachers can involve adjustments in the assignments of current teaching staff, consolidation or cancellation of classes, emergency hires that may involve requests for licensure waivers, perhaps the offer of financial incentives, but little more. More systematic responses that involve changes in policy require a view that looks beyond current need; in other words, they must consider projections of the future need for teachers.

The Approach to Current Need Estimates

There are different ways of thinking about the need for teachers and different approaches to developing estimates that reflect those differing conceptions. The different approaches use distinct kinds of data (or “data points”) and research methods to arrive at their estimates. And one state may use several approaches in order to examine the teacher need situation from varying, though not necessarily contradictory, perspectives as a way of cross-checking or “triangulating” across the different methods to account for the limitations inherent in each.

One way of conceiving of current teacher need in a state is as the balance of the demand for teachers in a given subject – in our case, in the sciences and mathematics – and the supply of teachers available to teach it. To calculate this balance, several different kinds of data are required:

  • Number of students taking classes in the subjects in question
  • Number of teachers licensed by the state to teach those subjects
  • State-mandated (or district-mandated) class size(s) or student-to-teacher ratio(s)

This calculation will yield a rough statewide estimate of the adequacy of the teacher supply in science and mathematics. Its accuracy is limited, however, because the number of licensed teachers in a state is generally far from identical to the number of teachers actually willing and available to teach at any given time. Moreover, because the statewide aggregate supply-and-demand calculation provides only a rough overall picture, it does not convey the important nuances of supply and demand in individual districts or schools that reflect the local economy and teacher labor market, working conditions, socio-cultural factors, and the resulting teacher retention and attrition rates. A state could have more than enough licensed science and mathematics teachers in the aggregate, but some districts still might have a shortage because of their inability to recruit the surplus teachers from other districts.

It is the express goal here to provide direction in developing a credible estimate of current need for science and mathematics teachers that is more rigorous and precise than the rough statewide estimate described above and that is sensitive to both local need and teacher quality. Although a state may experience a general teacher shortfall in science or mathematics that can be addressed effectively through statewide policy or market mechanisms, it is usually the case that any shortfall is more or less acute in specific schools and districts and that solutions must be appropriately tailored to local realities. Thus, good data on local conditions are of paramount importance. In addition, especially in view of the strong national priority that has been assigned to increasing the science and mathematics competence of our country’s youth, it is critically important to ensure not simply that we have enough teachers to cover the classrooms but enough teachers who are well-qualified and actually up to the task.

In view of these considerations, a more satisfactory approach to determining a state’s current need teachers – and the one offered here – would be to focus on the extent to which teacher supply has not met demand as manifest in immediate identifiable needs for teachers at the local level. These local needs are defined by two factors:

  1. Classes that had to be cancelled because no teacher could be found to staff them (and, ideally, classes that were not even offered in the belief that no teacher could be found)
  2. Classes taught by individuals whose qualifications are questionable.

Developing a Current Need Estimate

The following discussion offers three basic steps important for developing a thorough and reliable assessment of a state’s current need for teachers. Depending upon the accuracy of the data, the first two steps can provide a credible estimate of the current unmet need for teachers and a rough indication of the relative quality of teachers in the various districts around the state. The data for the third step are inherently less reliable, but they nevertheless can provide a basis for concluding that the state’s need for additional teachers may be somewhat greater than indicated in estimates based only on steps 1 and 2.

The suggestions offered here are not intended to address the technical issues of locating and synthesizing different sources of data and of building a solid teacher data system. Two independent sources provide good, detailed information on these important considerations:

  • Reichardt, Robert. (2003). Using Teacher Supply and Demand Analysis in Policymaking. Aurora, CO: McREL.
  • Voorhees, Richard A. and Barnes, Gary T. (2003, July). Data Systems to Enhance Teacher Quality. Denver, CO: SHEEO.

The Three Basic Steps

1. Gather the most reliable data possible, by school and district, on the number of science and mathematics classes in specific subjects that are staffed either by teachers who lack the state-defined normative qualifications or by long-term substitutes. This includes teachers who are teaching out-of-field or on emergency credentials.

These data reveal a state’s basic teacher shortfall by school and/or district and whether the problem is restricted to a limited number of schools and districts or is more widespread. The importance of collecting this information also points to two fundamental considerations that affect the ultimate utility and actual result of a teacher need estimate: its level of specificity and its inherent assumptions about teacher quality and teacher qualifications.

The more specific the needs analysis can be, the more satisfactorily it will guide efforts to address any shortfall or surplus. Ideally, the need for teacher should be based on the match of teachers for their individual teaching assignment.5 It is minimally helpful to determine a state’s need for mathematics or science teachers overall; the need should be expressed in terms of more fine-grained parameters involving subject and geography.

  • School level (elementary school vs. middle school vs. high school)

The science and mathematics curriculum differs greatly from one school level to the next, as do the academic and emotional needs of students. Thus, teachers at the various levels require different kinds of academic and pedagogical knowledge and skill to be successful. Every state recognizes these differences – especially between elementary teaching and secondary teaching – in its licensure categories. Some states go further and distinguish between middle and high school licenses. The needs analysis should at least reflect the need for teachers at the different state licensure levels.

  • Specific subject (e.g., biology, physics, earth science, mathematics, statistics)

Especially at the high school level, the content covered in the various science and mathematics disciplines is complex enough that few teachers will have strong competence in all of them even if they were a science or mathematics major in college. Thus, the need particularly for science teachers is best expressed as a need for teachers in a particular science discipline. The need6 for biology teachers, for example, is far less severe in most states than their need for chemistry, physics, and earth sciences teachers.

  • Course difficulty level (Advanced Placement, college preparatory, basic)

Within the science and mathematics disciplines themselves, the courses offered at the secondary school level are of varying degrees of difficulty. Teachers who are comfortable teaching basic level courses may not be comfortable teaching college preparatory courses or Advanced Placement courses. Although this fact is not always recognized in state licensure distinctions, many states do require teachers to earn some sort of specific credential (often an “endorsement”) that indicates their readiness to teach higher-level courses in their field. Thus, a needs analysis that addresses the coverage of courses at specific levels of difficulty provides more adequate and ultimately more helpful information than one which does not.

  • Geographic level

Although this tool is intended to facilitate the development of state-level estimates of teacher need, that need is ultimately a local phenomenon. A statewide shortage or surplus of teachers in mathematics or biology or physics doesn’t reflect the specific shortage picture for various regions of the state, let alone for specific districts or schools. If a need for teachers in a particular discipline is limited to specific locations in the state, the remedy may be to address local recruitment and retention issues or to ramp up teacher preparation in programs that specifically serve the localities affected by the shortage rather than to push for a statewide effort to recruit or produce more teachers overall. Thus, it is extremely important that statewide estimates of need be disaggregated to the regional and local level.

Adequate Qualifications

A guiding principle of this entire project is that it is ultimately impossible to separate the consideration of teacher need from the consideration of teacher quality. An assessment of the adequacy of a state’s teachers requires the ability to distinguish the teachers who have qualifications accepted as adequate from those teachers who do not. Unfortunately, there is no universally accepted or empirically validated definition of an “adequately qualified” teacher.

On one level, this consideration is related to the issue of the specificity of the need analysis. We noted previously the importance of specifying the need for teachers as a function of school level (middle school vs. high school), specific subject (e.g., “physics” and “chemistry” rather than “science” or “physical science”), and level of course difficulty (e.g., general mathematics vs. geometry II vs. AP calculus). Teachers who are adequately qualified to teach courses at some school levels and levels of difficulty will not be adequately qualified to teach courses at other levels. This is an especially important issue for science teachers because teachers who are qualified, for example, to teach general science at the secondary level may not be adequately qualified to teach any individual science subject at depth appropriate for the college preparatory or Advanced Placement level.

An additional complication in the effort to assess the quality of science and mathematics teachers on a course-by-course basis, however, is that science and mathematics may be taught differently in different districts and thus it may be difficult to identify the teacher expertise required uniformly across districts. If a district offers integrated science, for example, does adequate coverage require multiple science teachers with differing areas of expertise (who could co-teach such an integrated series of classes) or one teacher who is a science generalist?

Teacher Licensure

Not only is there no universally accepted or empirically validated definition of an “adequately qualified” teacher, but it is also a challenge to find the readily accessible data points in a survey of a state’s science and mathematics teacher corps that would validly and reliably signal the adequacy or inadequacy of individual teachers’ qualifications. State licensure is the logical candidate – indeed, by design – to meet both of these challenges. This would imply that states should consider a class as being taught by an “adequately qualified” teacher if he or she

  • Is fully licensed or certified, or has been issued a temporary credential based on active pursuit of a full license through enrollment in a formal teacher preparation program or other recognized coursework (e.g., a required state history course for recent teacher transfers in with a license from another state)
  • Is not teaching “out-of-field” – i.e., has the demonstrated subject knowledge required by licensure or endorsement in the field to be teaching the class
  • Is not a temporary substitute.

To be sure, state licensure is a blunt instrument, and it cannot ultimately ensure that every teacher who meets the criteria for licensure and for teaching a particular subject will be successful in teaching it. This is especially true for a complex field like science, in which individual science subjects are taught in a variety of curricular approaches. Basic licensure establishes a floor for teacher qualifications, and not all adequately qualified teachers are equally well-qualified or capable. Moreover, some individuals who lack all of the state-specified qualifications to teach a particular class may in fact be quite well-qualified for the task.

The Teacher Quality and Teacher Licensure unit of this project discuss these issues in greater detail.

2. Gather data, by school, on the years of experience of the science and mathematics faculty

Years of experience is a proxy measure for teaching competence that is valuable more as a bellwether of disparities in the quality of faculty between schools or districts than as any absolute measure of teacher quality. A significant body of research7 indicates that teachers’ skill and effectiveness tend to increase most significantly up to their fourth, fifth year, or sixth year of teaching and then improve much more marginally. In view of that research, the U.S. Department of Education requires states to indicate the relative experience of teachers in high-minority/high-poverty vs. low-poverty/low-minority schools as an indication of the comparative equity in teacher quality in those schools (NCLB Section 1111(b)(8)(C)).

Thus, it would be informative to group teachers, for example, into those with 0-2, 3-5, 6-10, and 11+ years of prior full-time teaching experience. The main point is to find some similarly segmented distribution that captures the percentage of experienced vs. inexperienced teachers in a way that could be indicative of their relative teaching proficiency. If the science or mathematics teaching staff of a school or district is significantly composed of teachers in their first few years of teaching, that may be an indication of high teacher attrition and diminished teacher quality – particularly in comparison with schools or districts with more experienced science and mathematics teachers.

3. To the extent possible, supplement the basic data on teacher need called for in steps 1 and 2 by collecting the following additional data:

  • The number of classes that had to be cancelled or could not be offered because adequately qualified teachers were not available to teach them
  • The degree to which hiring science or mathematics teachers was comparatively difficult – even if successful – in the various schools and districts and whether these difficulties are common statewide or limited to specific schools and districts. A shallow candidate pool can compromise teacher quality because it puts pressure on schools and districts to hire teachers whose qualifications might be less than ideal.

If an estimate of need is based only on the inability to hire adequately qualified teachers for classes actually offered, it fails to account for classes that may have had to be cancelled because no qualified teacher could be found or for classes that were not even offered because a principal or superintendent believed no teacher would be found. This is not an uncommon occurrence in rural schools, in particular, where the problem is further compounded by the fact that many schools are too small to hire an adequately qualified teacher for every subject (especially in the sciences). Collecting data on cancelled classes is difficult, however, because it may not be reported reliably or may be confounded by fiscal considerations. Not to try to collect it, however, is almost certain to ensure an underestimate of the number of teachers actually needed.

Regarding the difficulty of hiring teachers, states and districts have attempted to determine this in various ways. It often involves a survey of appropriate school or district administrative staff. Some surveys use a Likert scale and ask the person interviewed how difficult it was to hire teachers for specific courses – an inevitably subjective estimation that is likely to differ significantly from one individual to the next. Responses to such a survey can then be compared as to relative hiring difficulties between different subjects or between different schools and districts. Other surveys ask school principals or district administrators at some point after the start of the school year how many unfilled or vacant positions they have in science and mathematics.

The least problematic method is to use district administrative records (if these are available and reliable) to determine how many candidates applied for positions in specific subjects – thus indicating how large the pool was in mathematics or science relative to other subjects or how large it was for some districts or schools in comparison with others. While such a comparison of the number of applicants indicates nothing about the comparative qualifications of the candidates, schools and districts with relatively few applicants are certainly at disadvantage in ensuring the uniform high quality of their teacher workforce. And the closer the ratio of applicants to positions in science and mathematics is to 1:1, the more it indicates a potential shortage problem – especially if the ratio is significantly smaller in science and mathematics than in other fields.


1. We use the term “need” throughout this report to reflect the extent to which the supply of teachers meets the demand. “Supply” is used in this report to denote the available pool of teachers, and “demand” is used to denote the number of teachers required to staff the classes offered – and ideally, the number of classes that would be offered were the supply adequate to staff them.

2. By “appropriate” license we simply mean any sort of credential that authorizes an individual in a given state to teach science and mathematics courses. This could be a temporary license, for example, for teachers who are teaching while completing their formal preparation program. We discuss the issue of licensure in some detail in the Examining Teacher Licensure section of this report.

3.We use the term “need” throughout this report to reflect the extent to which the supply of teachers meets the demand. “Supply” is used in this report to denote the available pool of teachers, and “demand” is used to denote the number of teachers required to staff the classes offered – and ideally, the number of classes that would be offered were the supply adequate to staff them.

4. A state could experience a current need for teachers even though, numerically, there are a sufficient number of teachers to meet the demand. It may be the case that not enough of the teachers in the state’s apparent supply pool actually apply for or accept all of the teaching positions available in the various districts.

5. States should be prepared to undertake such a specific analysis because it is specified in the NCLB requirement that states report the percentage of classes taught by teachers without proper background and credentials (NCLB Section 1111(h)(1)(C)).

6. See Morton, B.A., Peltola, P., Hurwitz, M.D., Orlofsky, G.F., & Strizek, G.A. (2008, August). Education and Certification Qualifications of Departmentalized Public High School-Level Teachers of Core Subjects: Evidence from the 2003–04 Schools and Staffing Survey. Washington, DC: National Center for Education Statistics (Table 4, p. 25). Accessed at http://nces.ed.gov/pubsearch/pubsinfo.asp?pubid=2008338.

7. See, for example, Hanushek, E.A., Kain, J.F., O’Brien, D.M., & Rivkin, S. G. (2005, February). The Market for Teacher Quality. Cambridge, MA: National Bureau of Economic Research. Accessed at http://www.nber.org/papers/w11154. See Clotfelter, C.T., Ladd, H. F., and Vigdor, J.L. (2007). How and Why Do Teacher Credentials Matter for Student Achievement? Washington, DC: Urban Institute. Accessed at http://www.caldercenter.org/PDF/1001058_Teacher_Credentials.pdf.

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