In “A Study of the Grade K-6 Supplementary Instructional Materials Market”, the authors use instructional time used as a measure of the penetration of various materials and technologies. This is a much better surrogate measure of the penetration of new technologies and concepts into the market as it doesn’t depend upon the cost of the technology or material. (This approach should be the basis for a thorough study of the substitutions ongoing in the education arena.) However, the data is limited. What is does show is that CDROM and the Internet are gaining share of instructional time at the expense of other media, as shown in the graph below.
Data: Study of the Grade K-6 Supplementary Instructional Materials Market, Hagen Marketing Research Inc., Lois Eskin Associates & Professional Publishing Services, 2004
Ultimately, it appears that the Internet will be the primary method for computer based instructional delivery.