the exception of adult basic education , where CBI has an effect size between that of secondary and elementary school contexts . A variety of explanations have been offered for these differential effects ranging from the belief that teachers in lower grades are better at integrating CBI into the curriculum to the suggestion that there is less well-designed software available in the higher grades . Clark ( 1994a , b ) maintains that media and technology are mere vehicles for instructional methods . He provides an alternative interpretation of the differential effect sizes by arguing that when the differences in pedagogy are factored out of the comparisons between CBI and teacher-centered instruction , the effect sizes virtually disappear .
A more robust finding for computer-based instruction is that students are able to complete a given set of educational objectives in less time with CBI than needed in more traditional approaches ( Kulik & Kulik , 1991 ). The time savings factor was first identified in military training contexts where a consistent 25 % to 50 % reduction in time to train has been demonstrated when interactive technologies are employed ( Fletcher , Hawley , & Piele , 1990 ). The pressure to save instructional time has not been as great in school contexts , a situation that may change if proponents of national assessments are successful , and teachers perceive the need to cover more content within the school year .
Given the overall positive results for the computer as tutor approach , some questions can be asked about the relative effectiveness of different approaches to instructional computing in classrooms . The next two subsections of this report provide research findings for two major tutorial approaches : integrated learning systems ( ILS ) and intelligent tutoring systems ( ITS ).
Integrated Learning Systems
Integrated learning systems ( ILS ) utilize computer networks to combine comprehensive educational “ courseware ” with centralized management tools . ILS are marketed by large commercial vendors such as Computer Curriculum Corporation ( CCC ) [ www . cccnet . com ] and Jostens Learning Corporation [ www . jlc . com ]. CCC ’ s programs are reported to be in use by millions of students in 16,000 classrooms in the USA , Canada , UK , Japan , Australia , and New Zealand . Jostens claims that its courseware is used by 9 million students in 13,000 schools around the world . There were approximately a dozen major ILS vendors in the early 1990s , although recent mergers indicate that a market shake-out is underway . In a special issue of Education Technology magazine devoted to ILS , Bailey ( 1992 ) asked two primary questions : “ Why do they ( ILS ) continue to dominate the school technology market ? Are they as effective as the vendors claim ?” ( p . 3 ).
Why are ILS so popular among educators , at least those with the power to make purchasing decisions ? Bailey ( 1993 ) and Becker ( 1992b ) describe some of the perceived advantages of integrated learning systems that help to explain why ILS dominate the school technology market :
• Networking allows centralized management by teachers and administrators .
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