The LMS Toolkit is joining data from disparate systems into a common data model, the LMS Unifying Data Model (LMS UDM). That model is based on the use cases (see LMS Toolkit#UseCases) and also considers the natural state of the data as exposed by instructional systems. The LMS UDM provides a blueprint for the capture of learning management system data for K-12 education organizations.
The initial LMS UDM model was also based on the API capabilities of three large and popular learning applications; this list was identified and prioritized by members of the Ed-Fi community.
It is important to note that the model is not attempting to capture all data out of instructional systems: to do so would not be efficient technically, and much of the data would likely never be used. The project is therefore making careful choices to limit data to those elements the Ed-Fi community has identified as most useful.