Summary: We first estimated the number of physics teachers required to educate the current population of high school physics students in the United States. We then multiplied that number by a published rate of teacher attrition, resulting in the need for new teachers each year. This estimated need highlights the inadequate numbers of new physics teachers actually prepared across the nation.
We have also estimated what this need would be if all high school students took physics, which is a long-term goal of many educators. To simplify the calculation, we assumed that each 12th grader will have taken one physics class.
Calculations, assumptions, and sources of data
The number of high school physics teachers required was estimated based on the number of physics classes taught in each school. These data are available from the Civil Rights Data Collection. We assumed that in a given school, each 1-4 additional physics classes per year required 1 additional physics teacher. This results in an estimate of about 33,000 physics teachers in the United States, which is close to the total number of 27,000 physics teachers reported by the AIP Statistical Research Center (note AIP’s number excludes teachers at alternative schools and some other schools). The estimated number of physics teachers in a given state was calculated based on the estimated number of physics teachers in each school located in the state.
The number of new teachers was calculated from the total estimated population rate and an annual teacher attrition rate of 7% (see the "Teacher Attrition Rate" section below). The estimated total number of new physics teachers needed each year in the U.S. is about 2,200. This is greater than the number of new physics teachers actually hired, which is estimated at about 1,400 according to the Task Force on Teacher Education in Physics (T-TEP). T-TEP also found that teacher numbers were augmented by in-service teachers of other subjects who got assigned to physics.
Only about 40% of high school students take physics, according to the American Institute of Physics. If every student took physics, and we had enough qualified teachers to teach them now, we would still require a certain number of new teachers prepared each year to account for attrition. This figure (the first one shown on many of our Report Card on Physics Teacher Preparation pages) is 150% more (a factor of 100/40) than the number of new teachers needed for the current physics-taking population.
About The Teacher Attrition Rate
To calculate the level of need for teachers, we used a teacher attrition rate of 7.0%. This value is from Attrition of Public School Mathematics and Science Teachers, a 2008 issue brief from the National Center for Education Statistics, which reports that STEM teacher attrition is lower than the overall secondary teacher attrition rate.
Other related estimates of teacher attrition rates were considered but not used, including:
- The American Institute of Physics' Statistical Research Center estimates the attrition rate of physics teachers is 4%, based on its 2010 survey of in-service physics teachers.
- A 2009 report published by the Consortium for Policy Research in Education uses data from the Census Bureau’s Schools and Staffing Survey reports to identify the numbers of teachers in different subjects (English, Science, etc.) entering and leaving the profession each year. In the general subject area of Science, the ratio of the number of teachers who left the profession to the total number in the workforce gives an estimated attrition rate of 9.69%.