4.2 Sources of Usability
While the choice of software function was based on the type of data representation,
the choice of the particular software package was determined by convergences and
circumstances flowing from either the need for software to support learner oriented
objectives or pragmatic concerns about efficient authoring. No matter whether the
source of concern was educational or pragmatic, early or mid-project, a critical
characteristic of software across all projects was "usability" for the learner's
creation of their own materials or the author's editing of materials for the learners.