Michael B. Allen
This document summarizes the basic steps involved in developing supply and demand estimates for secondary science and mathematics teachers that were suggested in the report Improving State Need Assessments of Secondary Science and Mathematics Teachers: Challenges, Opportunities, and Recommendations. The report provides a more detailed explanation of the basic steps and of the conceptual, practical, and methodological issues that surround teacher supply and demand projections. The report also includes separate discussions of teacher data, teacher quality, and teacher licensure, which are not summarized here. And it includes, as a supplement, a downloadable technical review of the relevant methodological literature written by Steven Raphael.
The starting point for states’ efforts to identify their need for teachers in science and mathematics – i.e., the shortfall or surplus of teachers that results from the interaction of teacher supply and demand – is their analysis of their current need situation. The sort of current need estimate proposed here is fundamentally descriptive and employs present-time data to determine whether there is a sufficient number of teachers to cover the demand for classes. The approach focuses 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:
To develop an estimate of a state’s current need for science and mathematics teachers, the state should ideally have the following information at its disposal, 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,” if available, 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:
There are three basic steps 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 approximation 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:
Although the starting point for states’ estimates of their need for science and mathematics teachers should be the assessment of current need, it is the projection of their need for the future that is most important in shaping related policies and practices. At their best, however, such projections cannot be as confident as estimates of current need. The inherent uncertainty of the future, the reliance on statistical methods that make reasonable but not ironclad assumptions about human behavior, and the increased need for data that may be inaccurate or incomplete all compromise the validity of future need projections. Nevertheless, we attempt here to provide guidelines for generating estimates of future teacher supply and demand that are as reliable as possible. These include guidelines for projecting future supply and future demand independently, and then for the reconciliation of these two estimates.
1. To Determine Teacher Demand:
2. To Determine Teacher Supply:
In addition to the data related to developing rigorous forecasts of teacher supply and demand, a good analysis of a state’s currently employed teacher workforce can provide a few key data points that offer a preliminary indication (an “early warning”) of any emerging need for science and mathematics teachers that is likely to be particularly acute either across the state or in particular districts. One important caveat, however, is that data on a single year may be aberrant and not necessarily a sign of a trend.
If a high proportion of teaching slots are filled with new hires, this may be an indication of a serious turnover problem. This indicator is especially useful when comparing districts to one another or individual schools within a district
This is a proxy measure of the quality of the teacher workforce
The more teachers nearing retirement, the greater the likelihood that teachers will need to be recruited and developed to fill the impending departures.
The projection of a state’s need for science and mathematics teachers, whether short-term or long-term, requires independent projections of teacher supply and teacher demand. The guidelines offered here for developing a basic projection of teacher demand consist of five suggested steps:
1. Gather current and, if possible, historical data (preferably for at least the last 5 years) on the identified statewide need each year for secondary science and mathematics teachers
2. Determine current statewide student enrollment by specific subject (e.g., Algebra, Physics, and Biology) and course difficulty level (basic, college preparatory, Advanced Placement) in secondary science and mathematics courses, and track historical enrollments over at least the past 5 years if possible
3. Project future statewide student enrollment over the next 5-10 years for secondary science and mathematics
4. Derive a first-order projection of teacher demand for each science and mathematics subject over the next five years by multiplying the target class size in science and mathematics subjects by the projected student enrollments in the subjects for the next five years.
This will actually yield a projection of the number of classes that must be covered in the various science and mathematics subjects. To project the number of teachers required, further divide the number of classes to be covered by the average teacher course load
5. Refine the first-order projection of teacher demand
1. Gather baseline data on the teachers who are currently teaching science and mathematics courses throughout the state
2. Project the number of currently employed teachers in each mathematics and science discipline who are likely still to be teaching in the state in each of the next 5-10 years
3. Project the number of new science and mathematics teachers who are likely to be licensed and available to teach in each of the next 5-10 years
4. Construct a first-order projection of the available supply of science and mathematics teachers statewide by adding the number of teachers estimated to be available over each of the next five years from the various sources and subtracting the number of teachers anticipated to be lost through attrition each year
5. Refine the first-order projection of teacher supply
1. Determine the extent to which the projected statewide supply of teachers for the next 5-10 years matches the projected statewide demand for that same period
2. To the extent possible, reconcile statewide and district-specific projections
3. It is valuable to attempt to factor into the need projections the desire to have a surplus of applicants for science and mathematics teaching positions. This allows for greater selectivity in hiring and thus increases the likelihood of hiring better quality teachers.
This document was funded by the National Science Foundation through award number 0802359. Any opinions, findings, conclusions, or recommendations expressed are those of the author and do not reflect the views of the National Science Foundation.