The Learning Object Discovery & Exchange (LODE) specification aims to facilitate the discovery and retrieval of learning objects stored across more than one collection. It can be seen as a glue specification that profiles existing general-purpose protocols in order to take into account requirements specific to the educational domain, rather than creating new protocols. It proposes three main data models:

  1. A LODE Context Set for the Contextual Query Language (CQL): a data model for the attributes of learning objects, which can be used for search by expressing educationally meaningful queries;
  2. A data model, named Information for Learning Object eXchange (ILOX), that organizes sets of metadata on learning objects to be used in data exchange; and
  3. A data model, named Learning Object Repository Registry Data Model, for learning object collections, to be used in discovering and configuring access to those collections.

The Learning Object Metadata (LOM) standard issued by the Learning Technology Standards Committee (LTSC) of IEEE.

NSDL STEM Exchange - Paradata Initiative
The National Science Digital Library (NSDL) is a national network of digital environments dedicated to advancing science, technology, engineering, and mathematics (STEM) teaching and learning for all learners, in both formal and informal settings. In creating the concept of the STEM Exchange, NSDL needed to distinguish between traditional, relatively static metadata that describes a digital learning object and the dynamic information about digital learning objects that is generated as they are used, reused, adapted, contextualized, favorited, tweeted, retweeted, shared, and all the other social media style ways in which educational users interact with resources. In this context, paradata captures the user activity related to the resource that helps to elucidate its potential educational utility. NSDL has created a framework for generating and sharing paradata records across resource developers, aggregators, and user platforms.