Vocational courses for working professionals require them to attend classes only over weekends. Sometimes, even weekend classes are not possible because of strict deadlines at work. This audience, therefore, neither has the luxury of attending regular classes in a college environment nor does it have faculty available for clearing doubts. There is no access to a library for reference material or journals.
Their study material therefore must be complete in every way: self-instructional in nature with all necessary information, references and knowledge.