EBONI: Articles and Presentations

From the Visual Book to the WEB Book: the Importance of Design

Authors: Monica Landoni, Ruth Wilson and Forbes Gibb

First published in "The Electronic Library", volume 18(6) 2000, copyright MCB University Press.

Keywords: electronic books, electronic publishing, Internet, user studies, information retrieval, design

Abstract

This paper presents the results of two studies into electronic book production. The Visual Book study explored the importance of the visual component of the book metaphor for the production of more effective electronic books, while the WEB Book study took the findings of the Visual Book and applied them to the production of books for publication on the World Wide Web (WWW). Both studies started from an assessment of which kinds of paper book are more suitable for translation into electronic form. Both also identified publications which are meant to be used for reference rather than those which are read sequentially, and usually in their entirety. This group includes scientific publications and textbooks which were both used as the target group for the Visual Book and the WEB Book experiments. In this paper we discuss the results of the two studies and how they could influence the design and production of more effective electronic books.

1. Introduction

The result of integrating the classical book structure (i.e. the familiar concept of a book) with features which can be provided within an electronic environment constitutes a generally accepted definition of an electronic book. This type of book is designed to be an interactive document which can be composed and read on a computer. Conceptually it is an attempt to overcome the limitations of paper books by adding a series of added-value features which are made possible through the nature of an electronic environment. The main features of electronic books are that they are dynamic, reactive, can be made available in different formats and/or editions in a short time and, with the growth of the Internet, are accessible almost everywhere (Barker, 1991, 1996). However the translation from a paper to an electronic environment is not appropriate for every type of publication and for every type of reader. The process of reading and the tasks readers are attempting to complete have a central role in judging whether such a translation is suitable. The cognitive overhead associated with a computer-based environment is an important reason for carefully considering the appropriateness and the method of realising this conversion (Barker et al, 1994; Benest et al 1987).

The fact that technology is able to represent documents on the screen is clearly not sufficient justification for converting every piece of paper into electronic format. It is important to consider both the subject-matter and the intended usage of a particular paper book in order to decide whether an electronic version will be useful or not (Wilson, T., 1997). It seems clear that the desire or willingness to use electronic books is primarily based on the need for rapid access to information chunks rather than for assimilating significant amounts of narrative text (Leaver, 1995). An analysis of the market for paper and electronic publications showed that only a very small percentage of paper publications (a maximum of 10 per cent for even the most successful productions, such as encyclopaedias and dictionaries) are sold in electronic format, and that users prefer to keep a paper version in addition to the electronic one (Saur, 1996), even when a free electronic version is available via the World Wide Web (WWW) (Pope, 1999).

From the technological point of view electronic books need powerful processors, large amounts of storage, and the capability of managing combinations of different types of data. They are also increasingly dependent on access to telecommunications networks. The motivation for using electronic books is therefore partly constrained by the economic circumstances of the user. The motivations for producing electronic books therefore deal with factors related to the market requirement for electronic books, as well as cognitive issues related to the ability of the reader to use, appreciate and prefer books in electronic format to paper ones (Catenazzi et al, 1993). The quality aspect becomes crucial and for this reason the design process must be reviewed in order to create effective electronic books, i.e. communicators of electronic information which have additional value which paper cannot provide. This paper describes two studies into the design and production of electronic books: the Visual Book and the WEB Book.

2. Visual Rhetoric

The Visual Book experiment was a study into the application of the book metaphor to the design and production of electronic books with particular attention being paid to the role of visual components. The findings were the starting-point of the WEB Book study, which could be interpreted as an application of the guidelines provided by the Visual Book experiment to the production of WEB books; that is, books to be published, distributed and consulted using WWW browsers. The aim of the WEB Book experiment was to measure the improvement in terms of usability of a textbook published on the WWW with respect to presentation issues and to the overall appearance. The Visual Book provided the background and a set of guidelines for designing and producing scientific publications in electronic form, while a study on web page usability by Morkes and Nielsen (1997, 1998) provided the necessary methodology for studying the impact of design on reading and consulting material published on the WWW. This paper starts by discussing the importance of appearance and proper presentation style when creating an electronic book. The experiments and the findings of the two projects are then described and, in conclusion, a set of guidelines for electronic book design is discussed.

The novel aspects of the Visual Book studies were the importance given to the visual components of the physical book when designing electronic books together with the interpretation of an electronic book as part of an electronic library intended as an informative system with specific and innovative features. A new object, the electronic book, was studied within the context of an electronic library by following a new approach which highlighted and exploited the metaphor that relates the electronic book with its paper counterpart. The studies focused on a new aspect which had not been exploited to date: that of visual rhetoric, which is important to the design of both paper and electronic books.

The definition of visual rhetoric is tied, at least in the first instance, to the concept of spoken and textual rhetoric (Landoni and Gibb, 2000). Both are long established arts in which carefully composed and appropriately emphasised verbal constructs are used to improve communication. The idea behind visual rhetoric is to use visual clues in a similar way to identify or highlight those parts of a document which are more important for the comprehension of its meaning. Previous research has corroborated this view that a document can be interpreted as a visible representation of a text according to its semantic contents (Southall, 1989). Thus visual rhetoric is simply the translation into graphical terms of textual rhetoric based on both the logical structure of the text and its pragmatic component. It provides the reader with a graphical mark up language which is immediately recognisable on the basis of previous reading activity. Different graphical presentations suggest different readings and deeply affect the interpretation of the contents of the same text. These observations lead to the conclusion that visual rhetoric is a crucial aspect for both reading and browsing a document. In particular, when we move from the general class of electronic documents to the specific sub-class of electronic books, an additional concept has to be introduced: that of book rhetoric. Books are examples of the application of textual rhetoric as well as of visual rhetoric because of their physical nature and traditional presentation styles. Thus the term book rhetoric here stands for a combination of both visual rhetoric and textual rhetoric. The Visual Book project focused on the importance and use of visual rhetoric when presenting information on a screen and in particular on the influence of visual rhetoric in the presentation and use of electronic books. The study started from the comparison of the effect of visual rhetoric on the paper book and its impact on the presentation of the same book when it was translated into electronic form. A further step was to consider whether visual rhetoric could also have an impact on the design and presentation of electronic publications which had no paper counterparts.

3. The Visual Book Experiment

The Visual Book represents a particular interpretation of the electronic book, based mainly on the visual aspects of the paper book such as dimensions, thickness, page form, and general design style (Landoni, 1997). A Visual Book is the result of the process of converting an existing paper book into electronic form using two main components:

(1) The Visual Book Builder: the authoring system for building the Visual Book and consists of a Book Laboratory, (see Figure 1), where the page images are acquired and a Book Compositor, (see Figure 2), where the Visual Book is assembled by inserting the right textual/graphical component page by page.
(2) The Visual Book Browser: the module for presenting the Visual Book to readers see Figure 3).

Figure 1 Book Laboratory

Figure 2 Book compositor

Figure 3 The Visual book browser

The physical aspect of the paper book is the key to the construction and representation of a Visual book. Emphasis is placed on preserving the book's appearance in order to draw upon the familiarity the reader already has with books in general. Book functionalities were studied in terms of how books are used in practice to ensure that information is presented in a natural and familiar way and that the reading process is supported in an amenable environment.

An important point in the development of a Visual Book concerns the choice of which type of paper book should be translated (Landoni, Catenazzi and Gibb, 1993), as only certain publications are best suited to electronic publication. In the case of the Visual Book study scientific publications were chosen as they tend to be consulted rather then read in their entirety by users, and because these users are generally familiar with computers and are in a better position to appreciate the additional features and functionalities offered by electronic publication.

The main idea of a Visual book is to offer the reader an object as similar as possible to the paper book by replacing its essential physical features, such as size and quality, with visual ones. Another important principle in Visual book design was to determine which paper book features are more useful and familiar to the reader and to reproduce them in an electronic environment. Particular attention was paid to identifying those functionalities a Visual book could acquire from electronic support which would be most useful and consistent with the specification of the book concept. One of the main advantages of electronic support is the ease with which the designer can modify, update and distribute data (Catenazzi and Gibb, 1995). On the other hand, there is a series of functionalities, which already form part of the paper book environment, that are supported only in part by other electronic book models. These include:

Bookmarks.

Notes on the margins or elsewhere in the text.

Highlighting of interesting parts.

Easy access to pages which are frequently consulted by following different visual clues.

Information about the ratio between the pages already read and those remaining.

Control of the reading progress.

Browsing and scanning for interesting sections.

All of these have been incorporated as essential features of the Visual book browser, as shown in Figure 3. In particular search tools, such as an Index tool and Table of Contents (ToC), have been added to the Visual book features.

4. Visual Book Findings and Potential Developments

The evaluation of the Visual book (Landoni, 1997) concentrated on aspects of the book metaphor when converting paper books into electronic format. In particular the importance of maintaining the same typographical features, the design rules, the pagination format, and the paper appearance were considered carefully in terms of retaining the meaning of the original text. The physical aspects of the page are encapsulated in a set of presentation rules through which visual clues give the reader semantic information about the context. This primary feature of the book metaphor has been considered to be particularly important and to be an original contribution to the future development of the electronic design process. The effectiveness of traditional typography in presenting information through visual clues such as a specific choice of font, style, typefaces, headers, footers, justification and spacing rules, can also be considered to be valid in an electronic environment.

A number of criteria were extracted from other evaluations of the processes used when reading from a computer (Hansen and Haas, 1988; Egan et al , 1991) and these were used as the basis for the Visual book evaluation:

Sense of directness is the degree of feeling users have that changes on the screen are the result of their actions. It is connected with the illusion users have that the displayed image is a physical object which can be manipulated in the same way as a real paper book. A sense of directness helps users learn and internalise the interface to a system because every response by the system reinforces their confidence and understanding. In a system with a high sense of directness users can concentrate on the task that is to be accomplished without subjecting themselves to the cognitive overload of understanding system reactions.

Sense of engagement is the level of interest the system induces in users. The result of a good level of engagement is a high level of concentration that makes users interested in their task. One source of engagement is the fun of seeing the system react and is related to the novelty of the system; tangibility and responsiveness are also responsible for a good level of engagement. Paper has generally a low level of engagement because it is not interactive and is overly familiar to users.

Sense of text is the feeling users may have of the structural and semantic structure of the text that is being read, i.e. its spatial disposition. Readers are known to be able to recall the position of text in a paper text (Rothkopf, 1971). This fact connects a semantic entity, the information, with a physical one, which has visual and tactile cues. Factors which can influence the sense of text are the page size, legibility, and a low responsiveness while scrolling when looking for more text.

In general the results of the evaluation of the Visual book, which were supported by the findings of a similar project - the Hyper-Book (Catenazzi, 1994), showed that the book metaphor was both accepted and understood by its evaluators. These results also highlighted the necessity for a new role in electronic publishing, "the designer of electronic books, as the person in charge of the final appearance of the electronic book". This is a person competent not only in the technological aspects of producing electronic documentation but with a background in understanding the importance of presentation issues such as pagination and the general format and appearance of the electronic document, which can be called collectively electronic typography. This means that typographical rules are essential components of the cognitive model of a book and hence relevant to the translation of the metaphor of the book into electronic form. The importance of electronic typography has been proved by examining the state of the art of electronic publications, and the reasons for their relative lack of success, and comparing them with the history of the paper book through explicit analogies. All these issues have been summed up in the concept of visual rhetoric. The results of the evaluation of the Visual book system showed the importance of visual rhetoric as its application to the book image facilitates extraction of its logical structure and thus provides essential information to the designer of visual books.

It was clear that evaluators preferred the Index tool as being more book oriented (i.e. with a higher sense of text and engagement), and overall more satisfying than the table of Contents (ToC). However the ToC scored better in the sense of directness because of its relative simplicity when compared with the Index. It is important to point out that the ToC and the Index have very different roles in the book metaphor, even if both are navigational tools. In particular the ToC is mainly used for skimming the content of a book when readers do not know what can be found inside, i.e. as an explorative tool. The Index on the other hand has been designed to help readers find something they know about and wish to find inside the book, i.e. it operates as a searching tool.

The preference for using the Index tool can be interpreted as a tendency to use more sophisticated tools especially when they are fully supported by electronic medium. Even though the ToC was, as shown by the comparison in the case of the sense of directness, rated to be understandable and easy to use, the information contained in it is not sufficient for readers looking for a specific topic. This demonstrates that a good interface design and a successful mapping between the electronic book and the book metaphor is not enough to satisfy the reader. Access to information is still the main requirement and future design of electronic publications will have to consider this primary need. However, the presentation issue is also very important, as the comparison of the sense of directness shows: the fact that the Index is not as natural as the other tools for browsing makes it less direct to use. The same happens with paper books, where the index is usually hidden at the end of the book. In the case of the Visual book the evaluators were more interested in the Index functionality as the medium makes it a powerful and realisable tool whose implementation should be seriously considered during the production of electronic publications. Here was a case where the use of visual rhetoric was shown to improve the usability and effectiveness of tools which were already available in paper books. For example, the index was moved from its normal location at the back of the book to the front and made interactive, thereby increasing its visibility and ease of use.

The evaluation method which was applied to the Visual book was the cognitive jog-through (Rowley and Rhoade, 1992). In this approach, users were free to express, in written or verbal form, their comments and suggestions. One of the results of their positive evaluation of the Visual book system was a list of recommended future developments. In particular the evaluators felt that the Visual book browser should be expanded to incorporate more sophisticated features related to the capability of the computer. Users were happy to interact with an object which resembled a book and appreciated that its enhanced functionalities were consistent with the original paper version. The main request was for an intelligent search function to simulate and enhance the way readers search in paper books. Such a function should combine the precision provided by paper visual clues in defining the context of the search and by index terms compiled by a human indexer, with the higher recall provided by full text search which can be performed very efficiently using mainstream information retrieval software.

In addition to the comments from evaluators a number of future developments were identified by the research team based on their experiences. In particular the influence of the Internet on the presentation of information in electronic format should be studied in order to understand if modifications to the book metaphor and the related concept of visual rhetoric have to be considered to make it compatible with the Internet paradigm. Alternatively, the book metaphor may have to be imposed on the Internet paradigm in order to provide a consistent model with a cognitive background for the growing number of electronic publications available online. It is this issue that the WEB Book investigated and which is described in the next section.

5. The WEB book project

The WEB book was based on the central hypothesis of the Visual book project: that appearance is an important factor in the effective presentation of information on screen, and applied it to the production of books on the WWW. The aim was to study whether focusing on the appearance of the content when preparing a scientific textbook for electronic publication has a positive impact on its usability.

A series of studies by Morkes and Nielsen (1997; 1998) into how to write for the Web provided the basis for a methodology which would enable any improvement to be measured. They proposed that the usability of a text on the Web can be greatly increased by altering the presentation of the information to make it concise, scannable and objective. Their definition of what concise, scannable and objective text is as follows:

Concise text is where less-important information is edited out to reduce the page length.

Scannable text is written to encourage scanning, or skimming, of the text for information of interest. For this purpose bulleted lists, boldface text to highlight keywords, photo captions, shorter sections of text, and more headings, etc. are used.

Objective text presents information without exaggeration, or making subjective or unsustainable claims.

The advantages of using these modified versions are that:

Concise text contains less information to process.

Scannable text calls attention to key information.

Objective text avoids questioning the credibility of promotional statements that seems to distract users from processing the meaning.

When applied in their own experiments to a site with tourist information and a site with technical white papers (i.e. papers in progress), these changes led to increases in usability of 124 per cent and 159 per cent respectively. The WEB book project adhered to their procedure (Morkes and Nielsen, 1998) as closely as possible, and replicated the content of the questionnaires from their third study, using Chapter Five (Search Strategies) of van Rijsbergen's Information Retrieval (1979) as the material for the experiment (see Appendix 1). This textbook is one of the fundamental readings of IR, and a relatively plain machine readable version of the book already exists on the Internet.

Some modifications to Morkes and Nielsen's original procedures were necessary to suit the purposes of this research. Because a scientific textbook is primarily objective in nature, and cannot be made concise without either breaching copyright or compromising the meaning of the text, the emphasis in the WEB Book was simply on reworking the chapter to make it scannable by improving/redesigning its logical and physical layout. Certain items were omitted from the questionnaire, such as those asking users to rate how "entertaining" or "fun to use" they found the site, due to their inapplicability in assessing the usability of a textbook. Further, the study was carried out entirely over the Internet and so the "exam" used in the original became impractical, as did measuring the time taken for participants to complete the search tasks. As the experiment was being conducted on a different type of material its objectives varied from those of the original studies, so that browsing rather than searching for information in the text was encouraged making measurement of the time taken to complete the tasks less central to the purpose of the study.

The resulting methodology was used to test three hypotheses:

H1: Users of the revised, scannable version of the chapter will make fewer errors on tasks than will users of the original version.
H2: Users of the revised version will report higher subjective satisfaction with the site than will users of the original.
H3: When measures from the first two hypotheses are combined into an overall usability score for each version of the site, the scannable version will have a higher usability score than the control version (i. e. the original electronic version).

5.1 The WEB Book Experiment
Each stage of this experiment was carried out over the Internet. Participants consisted of 18 respondents to e-mails sent to two mailing lists for the IR community and to a group of postgraduate students who had studied IR in the Department of Information Science at the University of Strathclyde. By focusing on the IR community the intention was to target users familiar with the general subject matter of the textbook they would be asked to read, so that they could concentrate on browsing the site for information rather than being distracted by entirely alien content. Although mailing list respondents inevitably comprised a greater number of experts, similar numbers in each group had consulted van Rijsbergen's book before and the students were considered to have sufficient background in the field to be valid subjects in the experiment.

Two electronic versions of Chapter Five were used in this study: the original [1], and a revised version, written for the purpose of the experiment [2]. Of the 18 participants in the experiment eight looked at the original version of Information Retrieval, and ten looked at the revised version.

5.1.1 Design Issues
In the original electronic version only minor concessions had been made to the new medium. Each chapter is allocated a separate "page" (i.e. a Web page) and text is organised in a linear way so that users have to keep scrolling down until they reach the end of the chapter. Hypertext functions provided by Web browsers are used to provide certain basic structural links, such as moving from one chapter to the next. There are links from citations to bibliographic references, and links from the table of contents to the beginning of chapters have been inserted. Otherwise, it does not provide any more effective functionalities than those provided in the paper book. The revised version of this chapter was prepared for this study by the research team and followed Morkes and Nielsen's guidelines for improved scannability. The chapter was divided into ten separate files (Introduction, Boolean search, and so on) according to the sub-headings in the original text, so that each sub-section occupied a separate page. In addition, a chapter contents page was created to list and provide links to each section. Hyperlinks were exploited in order to aid navigation. At the top of each page, links were inserted to enable the user to jump back to the previous section, forward to the next section, or back to the table of contents for the chapter. At the foot of each page there was a list containing hyperlinks to each section in the chapter. Extra headings, coloured and sized, were inserted in the text in order to divide it into smaller, more digestible chunks. For example, the section headed Boolean search was allocated the additional sub-headings, What is Boolean searching?, Implementation and Modification. All diagrams were centred to give the pages a neater, more symmetrical appearance, and in order that they could be easily distinguished from the text. Key words and phrases were coloured red to call attention to important pieces of text, and lists were indented, their numbers or bullets also coloured red. These changes were intended to make the chapter more easily scannable by giving it a design which exploited more fully the functions of the Web as a medium.

5.1.2 Users
Students and mailing list respondents were asked to look in their respective sites for the answers to three search tasks. These tasks, the same for each group, were designed to involve participants in hunting through the chapter in search of specific facts; it was important to choose questions to which respondents were unlikely to know the answers automatically, but rather to encourage them to search in the text. Participants were specifically asked not to use their Web browser's find command in order to discover the answers to these questions, as the purpose of the study was to compare the usability of the two versions of the chapter according to the users' experience of browsing visually through the text.

5.1.3 Criteria
After completing these tasks, participants were asked to fill out a questionnaire (see Appendix II) about their experience which was intended to measure their subjective satisfaction with the site. Some questions asked about specific aspects of working with the site, and other questions asked for an assessment of how well certain adjectives describe the site. Following Morkes and Nielsen's guidelines, all questions were measured on 10 point Likert scales, and consisted of the following four criteria (see Morkes and Nielsen, 1997):

(1) Quality of the site. This contained three items: helpful, useful, and concise.
(2) Ease of use of the site. This included six items: easy to use, and the questions:

How easy is it to work with the text in this Web site?

How easy is it to find specific information in this Web site?

Compared to what you expected, how quickly did the tasks go?

How hard was it to concentrate on searching for information (because of distractions)? (this item was reverse-coded [3])

How confident are you that you found all the relevant information you were looking for?

(3) Likeability of the site consisted of four items: interesting, likeable, engaging, and unpleasant (reverse-coded [3]).
(4) User affect contained four items (all reverse-coded [3]): annoying, frustrating, and the questions:

How confused did you feel while working in this site?

How frustrated did you feel while working in this site?

5.2 Findings and analysis
The two major measures used to calculate the overall usability of each version of the chapter were the percentage of errors made in the search tasks, and subjective satisfaction (the culmination of all the individual elements of the questionnaire). These results are presented in Table I.

To determine how much better or worse in percentage terms the revised chapter was relative to the control, Morkes and Nielsen's procedure for normalising the participant groups' mean scores for the two measures was adopted. For each measure, the revised condition's mean scores were transformed by division relative to the control (see Table II), so that scores above 100 are better than the control, and those below 100 are worse.

Again following the original experiment, the overall usability score for each version was calculated by taking the geometric mean of the normalised scores for the two measures. (The geometric, rather than arithmetic, mean was used because ratios were being compared).

Table I. Mean scores for the two major measures, with standard deviations in parentheses

Condition Task Errors Subjective satisfaction

Original 16.67
(17.82) 5.10
(1.35)

Revised 6.67
(14.05) 7.55
(0.84)

Note: Task errors are percentage scores, and subjective satisfaction are the mean scores from the questionnaires, on a scale from one to 10.

Table II. Normalised mean scores for the two major measures and overall usability

Condition Task success (2) Subjective satisfaction Overall usability

Original 100 100 100

Revised 250 148 192

Table II shows that 150 per centfewer task errors were made by users of the revised version, and these participants recorded 48 per centhigher subjective satisfaction. Combined, this means an increase in overall usability of 92 per cent. The chapter which was rewritten to take into account the appearance of the content so that it was more scannable, achieved a higher score in every single measure than the original version of the text, and the three hypotheses were substantiated:

Hypothesis 1 was verified. Users of the revised version made 150% fewer errors on tasks than users of the original version.

Hypothesis 2 was supported. Users of the revised version reported 48% higher subjective satisfaction than users of the original version.

Hypothesis 3 was confirmed. Overall usability scores for the two versions of the site show that, compared to the control version, the revised version was 92 per cent better.

Participants' comments were in accordance with these results. Users of the original version of the chapter disliked the design of the pages, describing it variously as "flat and not very appealing", "very user-unfriendly" and "plain", with formulae that are difficult to read, making it hard to concentrate on searching for information. Users of the revised version, on the other hand, made some positive remarks about the page design, describing it as "easy to navigate" and "clean-looking", with one user commenting: "There was plenty of white space on screen and when the information being conveyed is fairly complex and takes a lot of thinking about (as this example does), I would find it very off-putting if the text was more crowded". Problems with the site were also identified, with one participant noting that the width of the lines of text, spanning from one edge of the screen to the other, made the chapter difficult to read, and another commenting on the problem of having to scroll up and down to compare the different diagrams and equations.

In this case study, making the chapter more scannable according to Morkes and Nielsen's guidelines led to a 92 per cent increase in usability, indicating the positive impact of focusing on the appearance of the content when preparing a scientific textbook for publication on the Web. Although the experiment was conducted on a small scale, these results are indications of the potential effect on usability of altering the appearance of texts on the Web to make them more scannable. It would benefit from being replicated on a larger scale, perhaps on the whole textbook, and with users from a wider range of backgrounds. Nonetheless, these indications are positive and in tune with the findings of previous exercises which form the background to the experiment. They reinforce the hypothesis of Crestani and Melucci's (1998) in which it is suggested that textbooks, because they are often used for accessing specific facts and pieces of information, are more effectively represented electronically in a non-linear fashion. Further, this research is in accordance with a key premise of the Visual book project, which states that a book's appearance is a main factor in the specification of interfaces designed to present information which has been published on paper.

6. Conclusions

The aim of the two projects described in this paper is to promote the definition of guidelines for the production of more effective electronic books. It is clear that to date only limited work has been done in that direction and that the emphasis in the production of electronic books has mainly been on creating the final product rather than on defining a paradigm or a set of rules in order to achieve an abstract object worthy of the label "electronic book". The definition of what an electronic book is, or has to be, is quite loose and unfortunately this is unavoidable because of the nature of the object and the difficulty of defining something with so many aspects and functionalities. In general the perspective of the whole Visual book and WEB book projects is centred on readers and their needs, expectations, cognitive models and requirements. The results of both experiments have shown that the book metaphor plays a crucial role in the definition of guidelines for the design of electronic books. These should consider that an electronic book has to resemble, be consistent with, and work according to some or all aspects of the book metaphor with no ambiguities, conflicts, inconsistencies or confusion. Therefore:

The page metaphor should be respected. That is, the page should be treated as a visual space where information can be easily found and scanned.

The logical structure of the book has to be considered. Table of Contents and Index(es) are essential features. These cannot be simply replaced by search facilities whose complexity makes the reading process more confusing for the user. This kind of mistake is usually the result of an enthusiasm for substituting and/or introducing computer-oriented features to the book system without considering their effects on readers which are used to consulting the paper counterpart.

The book template has to be used strictly to present information which is book related, and not any other kind of material as the result would be a heterogeneous system which could confuse users.

Titles, pagination, typographical aspects have to be designed carefully to enhance text readability and scannability.

Visual clues have to be adapted to exploit the potential of the medium where the book is published.

These guidelines were originally derived from the VisualbBook experience but have proven to be flexible enough to be applied to the WEB book. They are of particular interest to the designer of electronic books who has to be aware of the most practical aspects of the electronic book production and for this reason has to interpret the guidelines at the light of the medium and tools available. In fact they could be summarised in what Morkes and Nielsen (1997, 1998) recognised as the need for scannable text when the electronic book is going to be delivered on the WWW. Presentation and appearance play a crucial role in allowing users to read and use text in electronic form as much as they did and do with information on paper. Thus it is not surprising that guidelines for the production of good electronic books will have to take into account issues related to style and layout. The authors of this paper believe that greater emphasis on the observation of readers' reactions, can lead to the definition of heuristic rules for the production of "good" and "readable" electronic books.

Notes

1. Permission to use this material by the author is gratefully acknowledged.
2. This was "Task error" in the Morkes nad Nielsen original study (1997) but it was changed to avoid misunderstanding.
3. These items were reverse-coded because a high-scoring result indicated a negative response, in contrast to the other questions. For example, a tick in the tenth box on the Likert scale for "How confused did you feel while working in this site?" was interpreted as a score of one for the purposes of measuring user satisfaction. Likewise, a tick in the ninth box scored 2, the eighth box scored 3, and so on. In this way, responses to the negative aspects of the site were consistent with, and measurable against, responses to the positive aspects.

References and further reading

Barker, P. (1991). Interactive Electronic Books. Interactive Multimedia, 2(1), pp.11-28.

Barker, P. (1996). Living books and dynamic electronic libraries. The Electronic Library, 14(6), pp 491-501.

Barker, P., Richardson, S. and Benest, I.D. (1994). Human-computer interface design for electronic books. In: Raitt, D.I. and Jeapes, B. (eds.). Proceedings of the Online Information 94, 16th International Online Information Meeting, London 6-8 December. Oxford: Learned Information, pp. 213-292.

Benest, I.D., Morgan G., and Smithurst M.D. (1987). A humanised interface to an electronic library. In: Bullinger, H. J. and Shackel, B. (eds.). Proceedings of INTERACT'87. Amsterdam: Elsevier Science, pp. 905-910.

Catenazzi, N. (1994). A Study into electronic book design and production: Hyper-Book and Hyper-Book Builder. Glasgow: Department of Information Science of the University of Strathclyde (PhD Thesis).

Catenazzi, N. and Gibb F. (1995). The publishing process: the hyper-book approach. Journal of Information Science. 21(3), pp.161-172.

Catenazzi, N., Landoni, M. and Gibb, F. (1993). Design issues in the production of hyper-books and visual-books. Alt-J Association for Learning Technology Journal, 1(2), pp.40-54.

Crestani, F. and Melucci, M. (1998). A case study of automatic authoring: from a textbook to a hyper-textbook. Data and Knowledge Engineering. 27(1), pp. 1-30.

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Web references

1 http://www.dcs.gla.ac.uk/Keith/Chapter.5/Ch.5.html
2 http://eee.dis.strath.ac.uk/students/ruth/chpt5/

Appendix I: Electronic Text Usability Study: On-Line Forms

Patricipant's Details
1. Do you consider yourself to be an expert in the field of Information Retrieval?
Yes () No ()
2. Do you consider Information Retrieval to be one of your main interests? Yes () No ()
3. Is Information Retrieval the main focus of your research, or a side issue? Focus () Side issue () Neither ()
4. Have you read C.J. van Rijsbergen's Information Retrieval? Yes () No ()
5. If so, have you read the electronic or the paper version, or both? Electronic () Paper () Both ()

Tasks
Now please visit this Web site http://www.dcs.gla.ac.uk/Keith/Chapter.5/Ch.5.html where you will find chapter 5 of van Rijsbergen's Information Retrieval, and attempt to answer the following questions.

Please do not use the "find" command to look for the answers.

Enter your responses in the boxes provided.

1. What does the author cite as being the main difficulty with serial searches?
2. What is the name given to a cluster representative which is linked to the maximum number of other documents in that cluster?
3. What is the name of the search strategy which only allows AND logic but takes into account the number of terms the query has in common with a document?

Appendix II: Questionnaire
For each word below, please indicate how well it describes the Web site.

Click on the circle that best describes your answer.


              Describes                                               Describes 
              the site                                                the site
              very poorly                                             very well

Accurate                                            

Annoying                                            

Boring                                              

Concise                                             

Easy to use                                         

Engaging                                            

Frustrating                                         

Helpful                                             

Interesting                                         

Likable                                             

Useful                                              

Unpleasant                                          



Please click on the appropriate circle for each of the following questions:


How easy is it to find specific information in this Web site?

          not at all easy                                    very easy

                                              


How frustrated did you feel while working in this site?

          not at all                                         very
          frustrated                                         frustrated

                                              


Compared to what you expected, how quickly did the tasks go?

          not at all                                         very 
          quickly                                            quickly

                                              


How tired do you feel right now?

          not at all                                         very tired
          tired                                              

                                              


How easy is it to work with the text in this Web site?

          not at all                                         very easy 
          easy                                               
  
                                              


How hard was it to concentrate on searching for information (because of 
distractions)?

          not at all                                         very hard
          hard                                               

                                              


How confused did you feel while working on this site?

          not at all                                         very 
          confused                                           confused

                                              


How confident are you that you found all the relevant information you were looking 
for?

          not at all                                         very 
          confident                                          confident

                                              



Please use the space below to add any comments about this study or the chapter you 
have read.




You have now completed the form.

If you wish to know the results of the study, please e-mail me.

Thank you for your participation!