How Bad Is the U.S. STEM Teacher Shortage?
by Michael Marder, Executive Director of UTeach, The University of Texas at Austin
Since the publication of A Nation at Risk[1] in 1983, we have known there is a shortage of STEM teachers in the U.S. Has the problem of the STEM teacher shortage been solved now, almost 40 years later? It does not appear so.
In 1983, the authors made a clear statement: “Despite widespread publicity about an overpopulation of teachers, severe shortages of certain kinds of teachers exist: in the fields of mathematics, science, and foreign languages; and among specialists in education for gifted and talented, language minority, and handicapped students.”
In 2005, the authors of another report, Rising Above the Gathering Storm,[2] estimated that 200,000 teaching positions in secondary STEM would need to be filled over the following decade, and they recommended creating four-year scholarships to attract an additional 10,000 college graduates per year to STEM teaching.
The call for increased production of STEM teachers was renewed by President Obama, who in his 2011 State of the Union address called for the preparation of 100,000 additional STEM teachers over the next decade. An organization named 100Kin10 was founded to pursue this goal and to coordinate the actions of hundreds of organizations working towards it.
And still, the Educator Supply and Demand Report 2019–20 of the American Association for Employment in Education’s list of the hardest teachers to hire is exactly the same as the list in A Nation at Risk in 1983.
Is it possible to estimate the size of the current shortage? Existing data sources, even if not completely current, make this possible. One of particular value is the Civil Rights Data Collection, which provides a rich description of the coursework taken at every public high school in the country,[3] and the demographics of the students taking the courses. The most recent data are from 2017–2018.
To calculate teacher shortages requires value judgment. Students never sit alone all year in a room without a teacher, but schools use a variety of techniques to avoid this. Faced with shortages in specific areas, schools increase class sizes, hire substitute teachers, assign teachers who lack subject-area credentials or full certification, and refrain from offering courses they cannot staff.
High School STEM Teacher Shortages
I start with high school and provide a range of STEM teacher shortage estimates based on three separate standards.
1) Certified Teacher for Every Child. The shortage of teachers is defined by the additional number we would need to give a year of coursework in a STEM subject to every child during high school. Teachers without appropriate certification are to be replaced by those who have appropriate certification.
2) Some Teacher for Every Child. The shortage of teachers is defined by the additional number we would need to give a year of coursework in a STEM subject to every child during high school, but the teachers currently offering this coursework without appropriate certification are not to be replaced.
3) Certified Teacher for Most Children. The shortage of teachers is defined by the additional number we would need to give a year of coursework in a STEM subject to 80% of children during high school. Teachers without appropriate certification are to be replaced by those who have it.[4]
To compute the shortage in each scenario, I calculate a cohort size for every high school. This is the average of the students enrolled in 10th, 11th, and 12th grades.[5] Summing over all schools in the U.S., I get a high school cohort of 3.7 million students, which compares well with NCES data.[6] Next I calculate the total number of students in each school enrolled in each of the STEM subjects. I chose Algebra I as the mathematics topic most likely to be universal in high school. However, a large number of students take Algebra I in 8th grade, and I included this number as well. Finally, I assume that a Full-Time Equivalent (FTE) teacher teaches six sections of a class, and I use the national average class size in each subject to compute the number of students one FTE teacher will serve.
One could dispute these calculations saying the reason few kids take challenging courses such as Physics is that they choose to avoid them, not because teachers cannot be found. The example of Texas, where Physics was required, then made optional, but enrollment remained high, provides evidence that students will take challenging courses that preserve career options for the future if they have the choice.[7]
The Civil Rights Data Collection provides for each public school the number of sections of each subject, the number of sections taught by a teacher with appropriate certification, and the number of students taking the subject. The data also include the numbers of students in each grade. I assume the sections in a given school have the same numbers of students, and this lets me estimate the number of students in each school whose teacher lacks appropriate certification. For each science subject, the Civil Rights Data Collection says a teacher is appropriately certified if they have any science certification; therefore, this is not a very demanding standard. For Algebra I they need a mathematics certification.
In Table 1, I provide shortage estimates for Physics, Chemistry, Biology, and Algebra I according to the three standards described above. Summing only the positive shortage numbers, the shortages for these four disciplines range from 48,000 for the most stringent standard, to 25,000 for the most relaxed standard. The largest shortage is in Physics; there is no shortage in Biology. Is there really a shortage of math teachers, or does the fact that so many students are not taking Algebra I mean they are taking something else instead?
Although A Nation at Risk advocated at least half a year of Computer Science for all U.S. students — and this was decades before computing became as ubiquitous as it is today — the Code.org Advocacy Coalition (2019) finds that only 45% of schools in 39 states even offer computer science. The Civil Rights Data Collection does not yet include Computer Science, but this shortage must be at least as large as the shortage of Physics teachers, or at least 15,000 to 25,000 teachers. Thus, I estimate the high school STEM teacher shortage lies between 40,000 and 75,000 depending on the standard one sets.
Middle School STEM Teacher Shortages
It is more difficult to estimate teacher shortages for middle school than for high school. This cannot be done via courses students do not take; there is no middle school analog of Chemistry where one can argue that every student should have it and then count up the numbers who do. Instead, one must develop standards based upon teacher qualifications. I used the National Teacher and Principal Survey (2015–2016), which paints a surprising picture of middle school science and mathematics teaching.
Here are some observations from examination of the data. Less than 5% of middle school teachers teaching mathematics are certified to teach middle school mathematics and less than 5% of middle school teachers teaching science are certified to teach middle school science. I obtained these figures by looking at teachers spending an hour or more per week teaching these subjects and checking both their primary certification and an additional certification if they had one.
Around half of middle school math and science teachers are certified either as general elementary teachers or as special education teachers. The main additional certification of teachers with elementary certification is special education, and vice versa. Therefore, if one were to impose the standard that middle school STEM teachers have appropriate certification, the conclusion would be that almost none of them do. There are 11 million students in 6th through 8th grade, and if we estimate the number of FTEs to provide each of them a mathematics class each year with a class size of 15 and six classes per FTE, it comes to 123,000 teachers. The same number would be required to provide a science course each year. Thus, if we want to provide every middle school student with one science and one mathematics course each year from a teacher with mathematics or science certification, the shortage is 250,000.
This task is so daunting that it calls for a less ambitious standard. A suggestion comes by examining some additional feature of how middle schools staff their mathematics and science courses. A first observation is that 66% of all middle school teachers teach some mathematics and 40% teach some science.
Additional information can be gleaned from the fact that every teacher reports how many hours per week they spend on every subject. Figure 1 shows the percentage of hours of middle school mathematics and science taught by teachers as a function of the number of hours they devote per week. I will assume that the number of hours taught per week is proportional to the number of students. Then we see that 26% of middle school students take mathematics from a teacher who teaches it five hours a week or less, and 62% of middle school students take science from a teacher who teaches it five hours a week or less. Principals may be motivated to make such assignments by the fact that in some states a letter must be sent home to parents when a teacher is assigned out of field, but not if only one of their courses is out of field.
The data further show that middle school teachers only spend 35% as much time collectively teaching science as they do teaching mathematics. Thus, I conclude that while students get mathematics every year in middle school, they get science only once.
A minimal expectation for middle school STEM would be the following: Every middle school student will take mathematics each year from a teacher who teaches at least 20 hours of mathematics per week and will take at least one science course in middle school from a science teacher who teaches science at least 20 hours per week. Only 20% of current middle school science and mathematics teachers meet this standard. It would take 130,000 new teachers to fully meet this standard. This is a lower estimate of the need for middle school STEM teachers.
The bottom line is that even if one sets a low standard, the U.S. has a shortage of 180,000 middle and high school STEM teachers, and if one sets a higher standard, the U.S. has a shortage of 350,000 middle and high school STEM teachers.
Here I have simply estimated overall shortage numbers, without asking for which groups of students the shortages are most severe. It will come as no surprise, although it calls for further analysis, to say that shortages most severely impact students from marginalized groups, including low-income, Black, and Hispanic students. The hope of providing equitable education to all students will remain a hope unless the problem of STEM teacher shortages is solved. Therefore, addressing this problem is one of the most significant educational challenges of our time.
[1] https://www2.ed.gov/pubs/NatAtRisk/risk.html
[2] https://www.nap.edu/catalog/11463/rising-above-the-gathering-storm-energizing-and-employing-america-for
[3] In 2019 there were 51 million public school students and 6 million private school students in the US. The Civil Rights data covers only the public school students.
[4] This definition is motivated by the fact that Texas (nearly) meets this standard for high school Physics, the hardest subject to staff. If Texas can do it then it should be practically achievable.
[5] I leave out 9th grade because this is a grade level in which sometimes students have deliberately been retained for more than one year because of accountability measures, and 9th grade enrollment may be inflated. Inflation of 9th grade enrollment has been a factor in Texas although this may not apply to the rest of the country. Excluding 9th grade does diminish the size of the cohort.
[6] https://nces.ed.gov/programs/digest/d19/tables/dt19_203.10.asp .
[7] https://www.aps.org/publications/apsnews/201910/backpage.cfm
