Link: IMS Question and Test Interoperability v2.1 (pdf).

Providing a decade of interoperable assessment, IMS Question and Test Interoperability is a widely used specification for managing and sharing assessment material. Now that we are near the release of the final version of QTI v2.1 this paper provides an overview of the specification, outlining some of the key features of QTI v2.1 and its value for developers and educators. The intended audience for this paper is managers, learning technologists and developers interested in online and electronic assessment and new to QTI.

[pdf http://publications.cetis.org.uk/wp-content/uploads/2011/10/qti_v21_briefing.pdf]