School spending for professional development
The total K-12 professional development market in the United States has been sized at $18 billion as of 2015, the latest year for which data is available. Public schools spend an average of $148,337 per year on professional development for its teachers; while private schools spend $98,946 per year. A deep dive of my findings, including my methodology and calculations, is below.
To find the average amount of money that K-12 schools in the United States are spending on professional development for their teachers, principals, and superintendents, I first searched for official studies, which led me to the New Teacher Project report from 2015, which is the most recent comprehensive study completed on professional development spending in K-12 schools. As it is still referenced frequently by current publications, I assumed that this is the most recent data available. Thorough research did not reveal any more recent studies with the same level of information.
Unfortunately, this study only provides information on the amount of money spent on professional development for teachers. There is no information on how much money is spent on superintendent or administrator professional development. It is my assumption that superintendent and administrator professional development does not represent a significant portion of a school district's budget and has thus not been adequately studied. Therefore, the information presented here only reflects K-12 spending on professional development for teachers.
According to The New Teacher Project Study in 2015, a total of $18 billion is spent annually on professional development. In addition, this same report found that "schools are spending as much as $18,000 per teacher, per year on professional development." However, since this study only "spanned three large public school districts and one midsize charter school network," and only included surveys and interviews from "10,000 teachers, 500 school leaders, and 100 staff members involved in teacher development," I determined that while some large schools are spending upwards of $18,000 on professional development, this does not reflect the average spend of a typical K-12 school, public or private. Therefore, I decided to only use the market size from this study to extrapolate the data for all K-12 schools in the United States to provide a more accurate spend per school on professional development.
To extrapolate the data from this study, we used the following statistics derived from the National Center for Education Statistics, which provides the most up-to-date data on K-12 education in the United States:
In the United States there are:
-98,200 public schools (K-12)
-34,600 private schools offering kindergarten or higher grades
-3.2 million full-time-equivalent (FTE) teachers in public K-12 schools
-400,000 FTE teachers in K-12 private schools
In addition, a study comparing public schools to private schools found that "85 percent of public school teachers participate in some form of professional development every twelve months compared to 67 percent in private schools." This data will be used to approximate the number of teachers per school receiving professional development.
The $18 billion market size for K-12 professional development will be used in all calculations.
Average spend for K-12 professional development per school: $135,542.00 ($18,000,000,000 / 132,800 = $135,542.17, rounded to $135,542.00)
Therefore, we can say that the K-12 schools (both public and private) spend an average of $135,542 per year on professional development for teachers.
To determine how much public schools spend versus private schools on professional development, though, we need to use the proportion of private schools to public schools to segment the total market. Of the 132,800 total K-12 schools, public schools represent 74% (98,200 / 132,800) and private schools represent 26% (34,600 / 132,800). Using these percentages, we can assume that public schools spend 74% of the total market or $13,320,000,000 ($18,000,000,000 x 0.74) and that private schools spend 26% of the total market or $4,680,000,000 ($18,000,000,000 x 0.26).
However, it is likely that private schools spend less on professional development because they generally have smaller budgets. For example, a teacher with 10 years' experience in a public schools earns an average salary of $54,860, while a private school teacher with the same experience earns an average of $40,440. If we use a proportion of $40,000 to $55,000, this means private schools spend an average of $8 per teacher for every $11 per teacher spent by public schools. Using this proportion, we can break down the average expenditure on professional development even further. Private school teachers earn 73% of what public school teachers earn (8/11 = 0.727 rounded to 0.73). As such, I assumed that private schools will spend about 73% of what public schools spend on professional development as well. Please note that this ratio is only representative. The actual ratio of professional development spend for private and public schools is unknown.
Therefore, if public schools spend $135,542 (13,320,000,000 / 98,200) per school, private schools would actually only spend $98,946 per school ($135,542 x 0.73 = $98,945.66, rounded to $98,946), a difference of $36,314 from the unqualified average of $135,260 ($4,680,000,000 / 34,600). This means an extra $1,256,464,400 ($36,314 x 34,600) is allocated to public school spend, adding an extra $12,795 per public school on average ($1,256,464,400 / 98,200 = $12,794.95, rounded to $12,795), increasing the average spend per public school on professional development to $148,337 ($135,542 + $12,795)
If 85% of public school teachers participate in some form of professional development every 12 months, we can say that schools pay for an average of 28 teachers to receive professional development each year (33 x 0.85 = 28.05, rounded to 28).
Average professional development spend per public school teacher: $5,298 ($148,337 / 28 = $5,297.75, rounded to $5,298).
If 67% of private school teachers participate in some form of professional development every 12 months, we can say that private schools pay for an average of 8 teachers to receive professional development each year (12 x 0.67 = 8.04, rounded to 8).
Average professional development spend per private school teacher: $12,368 ($98,946 / 8 = $12,368.25, rounded to $12,368).
Summary of findings
Knowing that the calculations are extensive, I have provided a summary of findings that are derived from the above calculations.
Total U.S. K-12 professional development market size: $18 billion
Average K-12 professional development spend per school (both public and private): $135,542
Average K-12 professional development spend per public school: $148,337
Average K-12 professional development spend per private school: $98,946
Average K-12 professional development spend per public school teacher: $5,298
Average K-12 professional development spend per private school teacher: $12,368
Of the $18 billion United States K-12 professional development market, the average public school spends $148,337 per year, while private schools spend an average of $98,946 per year.