Week 10 Reading Notes

Digital Library Design for Usability

This article outlines five models of computer systems design. The authors find several of these models lacking. The most successful design elements gleaned from these five models include:

• Learnability: the user can start using a digital library quickly without picking up a lot of new skills.
• Memorability: the user can remember how to use the library after a significant length of time.
• The user should be able to recover from errors.
• The user should be able to save search results or search paths for later use.
• Users within an organization should be able to get training and guidance on using the library.
• Library prototypes should be tested on end users and revised before the final product is released.
• Proactive "agents" that know a user's preferences can alert her to new items of interest.

Evaluation of Digital Libraries: An Overview

Saracevic's typo-riddled article points out that evaluation of digital libraries, especially commercial libraries, is rare. When digital libraries are evaluated, a systems-centered approach is most common. Human- and user-centered approaches are less common. To me this is problematic; if digital libraries are used by humans, their needs should be evaluated first. Perhaps this is why Saracevic notes that "users have many difficulties with digital libraries" such as ignorance of the library's capabilities and scope.

I strongly disagree with his assertion that "it may be too early in the evolution of digital libraries for evaluation." Even when he wrote his article in 2004, many digital libraries were in existence. Now there are even more, and the number is growing all the time. Institutions spend hundreds of thousands of dollars on commercial digital libraries alone, so they should have some evaluation results on which to base their funding allocations.

Arms Chapter 8: User Interfaces and Usability

Arms details some reasons for the disconnect between end users and digital libraries. First, the interfaces, collections, and services in digital libraries change constantly, but the user adapts slowly. This can cause much frustration. Second, digital libraries were initially used primarily by experts who understood what they were using. Now that the Internet is nearing ubiquity, fewer digital library end users are experts. They "do not want to spend their own time learning techniques that may be of transitory value." Thus digital libraries must be accessible to both skilled and unskilled end users.

Arms lists four parts of a digital library's conceptual model: interface design, functional design, data and metadata, and computer systems and networks.

Several points stood out to me:

• To increase space on the screen for content, remove on-screen manipulation buttons and have the user navigate with keystrokes.
• Structural metadata is required to relate page sequence with actual page numbers. The page number in the original document rarely matches the sequence of the digital version, since prefaces and tables of contents are seldom numbered.
• To reduce the time of page loading, data can be sent to the user's computer before she requests it. If she is viewing page 6, for instance, the computer can "pre-fetch" page 7 in the meantime.

Some of Arms' suggestions for digital libraries:

• They should be accessible from anywhere on the Internet.
• The interface should be extensible.
• Content should be accessible indefinitely. (This tenet seems under threat by copyright laws and DRM.)
• Interfaces should be customizable.
• Spacial representations of library content can aid the user's memory and increase access.
• Interfaces should have consistent appearance, controls, and function.
• The interfaces should provide feedback to users about what is happening.
• Users should be able to stop an action or return.
• There should be several ways for the user to complete the same task; some routes can be simple for the novice user while some routes can be faster for experts.
• Interfaces should be accessible regardless of a user's computer display preferences, Internet speed, or operating system.
• Caching and mirroring should be used to reduce delays in information transfer over the Net. Through mirroring, the user accesses the content closest to her, though it may be stored on several servers around the globe.
• Summarize the user's choices.