As with any rapidly changing technology and marketplace, the terminology around XR technologies is highly fluid. However, four terms crop up often and, to a certain extent, overlap: virtual reality (VR), augmented reality (AR), mixed reality (MR), and extended reality (XR). Many discussions of these technologies reference the concept, first proposed in the mid-1990s, of a "virtuality continuum" (see figure A1), from entirely real to entirely virtual.1 On one end of this continuum is the physical world, and on the other end is VR— an entirely simulated environment. In between those two poles is MR, which encompasses AR and augmented virtuality (AV)—AR is the physical world augmented with virtual objects, while AV is a simulated environment augmented with physical objects. Even the authors of early papers about the virtuality continuum admit that as graphics rendering technology improves, it will become increasingly difficult to determine whether augmentations, and even the environment being augmented, are physical or virtual. We are not yet at that point in technology development, but we are perhaps not far off: think about how realistic computer-generated imagery (CGI) in movies can be. Nevertheless, in the virtuality continuum, both AR and AV are points on the spectrum of MR.

Since those early publications on the virtuality continuum, these terms have shifted. The term AV is no longer widely used. The term AR is used to mean the physical world augmented with virtual objects, but those virtual objects are static, mere overlays atop the physical world. Many AR applications have been developed for museums and for specific museum exhibits. The Franklin Institute in Philadelphia, for example, deployed an excellent AR app for the touring Terracotta Warriors exhibit. The term MR (and the emerging term "hybrid reality") is also used to mean the physical world augmented with virtual objects, but those virtual objects are interactive: the user can affect the state and behavior of these virtual objects, and these virtual objects may also affect the state and behavior of physical objects. A research project at Harvard University, for example, is developing MR overlays for learning electronics in which the user can see and change the flow of electricity and the magnetic fields around a simple audio speaker.

The use of these terms in association with commercial products is where things often get confusing. The HTC VIVE, for example, is marketed as a VR headset, but some newer models contain forward-facing cameras (also called "pass-through" cameras) that allow the user to view the physical world in the headset. Some newer models of Microsoft Windows–compatible headsets also contain pass-through cameras and are marketed as mixed reality headsets.

A cardinal rule of educational technology is that the technology used should follow from the educational use. VR, AR, MR, and even AV all have potential pedagogical uses. Part of the purpose of this report is to explore and suggest what those purposes may be. To include the broadest possible range of simulation-based technologies in discussions about their instructional use, therefore, EDUCAUSE has opted to use a broader term: extended reality (XR).2

This study used the multiple case study method,3 with the phenomenon under study being the use of XR technology for teaching and learning. Participating institutions were selected as exemplary cases:4 institutions that participated in phase 1 of the Campus of the Future project were selected because of their depth of experience with XR technology and the larger number of use cases on campus; institutions with little or no prior experience with XR were selected specifically to be as different from these phase 1 institutions as possible.

A total of 17 educational institutions in the United States participated in this research project (see appendix C). A total of 33 interviews were conducted with 36 individuals at these institutions between January and May 2019. The interviewees spanned a wide range of jobs: instructors at all levels, deans and directors of academic units, librarians, instructional designers and directors of campus centers for teaching and learning, and C-level institutional leadership. These individuals were identified via snowball sampling, starting with the individual who is HP's primary institutional contact for the Campus of the Future project.

The primary data collection method for this project was semi-structured interviews. These interviews elicited detailed information about the interviewees' involvement in using XR technology. The interviews were supplemented by document analysis: where they were available and interviewees were willing to share them, course syllabi and research proposals were collected for courses and projects in which XR technology was used. Further, project teams at some participating institutions had created blogs to document the progress of XR-related projects; these posts became a data source about use cases on campus. Similarly, news articles in campus publications and the higher education press about participating institutions provided some information about campus use cases. Finally, some interviewees had published articles, or referred to publications by their colleagues, about XR in their discipline. These documents were used primarily to inform the creation of interview prompts.

A total of 17 educational institutions in the United States participated in this research project:

• Barnard College
• Bryant University
• Bucks County Community College
• Columbia University
• Dartmouth College
• Florida International University
• Foothill-De Anza Community College District
• Hamilton College
• Harvard University
• MIT
• Morgan State University
• The New School
• North Carolina School of Science and Math
• Syracuse University
• University of Pennsylvania
• Wake Technical Community College
• Yale University

These institutions were not representative—nor were they intended to be—of the state of higher education in the United States or globally. These institutions were selected as critical cases;5 that is, they were chosen specifically for their informativeness about the use of XR in higher education. Institutions with prior XR experience are naturally going to be further down the road of implementation and deployment—and integration of the technology into teaching—than institutions with little or no prior XR experience. The wider the range of XR experience at participating institutions, the more informative these cases could be.

Some of the institutions that participated in this study also participated in the previous Campus of the Future project, described in the 2018 Learning in Three Dimensions report. Those institutions are mostly four-year, doctoral, research-focused institutions, and they had at least a year's worth of experience with XR when this project began. Institutions with little or no prior XR experience were therefore selected specifically to be as different from these as possible. These less experienced institutions were those with smaller student populations (e.g., Barnard College and Morgan State University) or that serve a different student population (e.g., community colleges).

The makeup of these participating institutions was as follows:6

• Most were four-year doctoral universities with high or very high research activity.
• One was a four-year master's institution: Bryant University.
• Three were four-year baccalaureate institutions: Barnard College, Hamilton College, and Foothill College (one of the two campuses of the Foothill-De Anza Community College District).
• Three institutions were community colleges: Bucks County and Wake Tech Community Colleges are two-year associate's colleges. Foothill-De Anza Community College is actually a community college district of two campuses, one a two-year associate's college and one a four-year baccalaureate college.
• One institution was a historically black college or university (HBCU): Morgan State University.
• One institution was a high school: the North Carolina School of Science and Math (NCSSM), a two-year public residential high school with a focus on STEM disciplines.

The Learning in Three Dimensions report presented a broad brushstroke overview of XR technology in higher education. Because this study delves deeper into the adoption and implementation of XR technology, it consequently casts a wider net of institution types.7