Return on investment with respect to employee training is a growing phenomenon in business and industry, as understanding the impact of training on an organization is often not enough. Public educational systems also spend a significant amount of resources on professional development. However, because education is a non-revenue generating industry, rarely do we analyze return on investment in the educational sector. This article examines return on investment for public school teacher training and professional development. While this model was developed for a specific school system and software, the model outlined below may be used by administrators in many non-profit or social organizations to determine a professional development return on investment.