This article discusses the design of Concept Mapped Project-Based Activity Scaffolding System (CoMPASS) and the theoretical foundations that it is based on. CoMPASS is a hypertext system that presents students with external, graphical representations in the form of concept maps as well as textual representations both of which change dynamically as students traverse through the domain and make navigational decisions. In a study in which middle school students used CoMPASS, students' navigation paths, as well as their learning outcomes, were analyzed. A comparison class in which students used the system without the maps for navigation provided information about students' use of the maps for navigation and its effect on their learning. It was found that students who used the maps version of the system performed significantly better in a concept mapping test as well as an essay test, and their navigation was more focused. This article discusses the findings of the study and its implications for designing hypertext systems.

It is important that all pedagogical design decisions in educational learning environments are made explicit to the educator. However, implicit assumptions affecting or even contradicting the "official" pedagogical method may unbeknownst slip into the design. We discuss a concrete problem in the area of adaptive hypermedia systems related to the notion of a prerequisite. Prerequisites are frequently used to describe the many different educationally effective paths on which learners may traverse a hypermedia system. However, a closer look reveals that several different concepts are called prerequisite and confusing them may lead to flawed designs. We make recommendations as how to avoid misusing the different notions of prerequisites in adaptive hypermedia systems.

Web page prerequisites can be used to constrain how a user can explore a web site. This can be used in a number of ways, but plays an especially important role in educational sites. If disjunctive and conjunctive constraints are used to describe the preferences, some pages may become redundant given the user's previous path and the user may not want to visit them. The redundancy of a page is not a local property and may depend on many preferences. This paper describes an efficient algorithm that finds these redundant pages and discusses some applications of the approach.