PD3 consists of a classroom visit data collection tool on a handheld computer, and a website that enables users to generate online reports based on aggregated classroom visit data.

The design of the mathematics and science components of the PD3 tool reflects the cognitive classification system (Webb's "Depth of Knowledge") used to develop the Florida Comprehensive Assessment Test (FCAT).

PD3 Online Reports use the data collected about the instruction and content of the lesson to guide a school's or district's professional development decisions for teachers within grade levels or subject areas.

PD3 was developed for the Florida Department of Education by the Miami Science Museum and SRI International. The PD3 reading component was developed by Miami-Dade County Public Schools, the Florida Center for Reading Research, SRI and the Museum. Funding for PD3 training is provided by the Florida Department of Education William Cecil Golden School Leadership Development Program.