The art of effective instructional design in distance education depends largely on making the right selection among media for each particular content and each type of learner within various constraints, particularly those of cost. Significant considerations include access to expertise in designing good-quality programs for available media and the availability of support services to the learners who use them, usually through the provision of support personnel in the learners' localities. Consider the learners. Recorded media can be delivered to any number of students, although other considerations may not make this practicable. Motivation is probably the single most important variable determining learning at a distance or in other educational environments.
Previous education is also extremely important.
Increasing motivation and therefore enhancing learning outcomes can help institutions and organizations recoup much of their investment in education or training. Consider the content. Content needs to be analyzed to identify which parts can effectively be communicated by text, which require the spoken word and other audio attributes, which can better be illustrated visually, and which need interaction. If it can be assumed that recorded materials alone will be sufficient, there is no need for interactive media. However, it is seldom the case that most learners in a class will achieve learning goals as well independently as by participating in discussions, project activities, and similar interactive experiences.