Internet is an integral part of today’s society and World Wide Webs are the most common used method for information sharing over it. Also called as Web in short, are built with certain purpose, targeting certain group of users, to fulfill an objective. That objective could be advertisement, information, news or something else. They are termed to be successful if they can fulfill those objectives efficiently. Since they are designed for users their success depends upon the number and frequency of their user. Higher the user and/or higher the frequency of returning user more successful is the web. For this web
This article is not a complete study by any means. It is intended to cover the major concepts, factors, terminologies, metrics related to web usability. The work was done as the part of assignment. Few but latest and important literatures and experience were used as the reference.
Internet is inseparable part of modern World and web is the most common information sharing method over it. It is used almost in all aspects of today’s life. They act as the means of advertising, information providing, interacting, source of entertainment, means of communication etc. and many more. Nowadays we even have Web shops, Web seminar, online jobs etc. which has no physical existence but only with web.
There is an increase in number of web day by day. It is believed to reach 1 billion by the end of 2014 from just 1 in 1991 . This increase in number automatically brings competition among similar kind of webs. Similar kind of webs target similar user groups. These groups are and will get divided among these webs. There is a fierce competition between them to attract and retain more users to be successful. For this, proper attention is to taken during its design. They need to be user centric and need to possess properties that are cherished by them. These properties or factors needs to be studied extensively. They are of high importance for web to survive in the competitive environment. Also these factors ensure user get better quality web applications. Additionally, studying doesn’t do any good if we don’t measure and record them. Measuring and recording will help analyze, study, compare, contrast and improve between webs. It will also in turn help to generalize factors and their relative measurement required to have success web which can act as a rule of thumb for successful web.
2. What is Web Usability?
ISO 9241 defines usability with aspect to types of user group, goals of web and the context of its use. It is “the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use” .
Nielsen considers ease with which the user learns to use the application. Besides considering ease of use and application effectiveness and efficiency and he defines usability as the combination of five components: learnability, efficiency, memorability, errors and satisfaction .
Abran et al. enhances Nielsen definition  and proposes a new model, called as Consolidated Usability Model . The model defines usability as the combination of efficiency, security, effectiveness, satisfaction and learnability. And also recommends suitable measures for those components .
Web Usability takes various human and non-human aspects into consideration, thus it is a complex thing to define. It has been defined by many researches and there exist many more definition than mentioned above. Those definitions are not exhaustive by any means. Researches are still being done in the field and it is expected to change now and then, along with the change in understanding. But, almost all the definition has one thing in common, “ease to use” and it dependency upon various factors. These factors differ slightly between researchers and definitions.
3. Factors affecting web usability
Web usability is a broad field and many factors can affect it. As the definition of usability, researches have added/reduced factors in the past that they perceive plays a role. This will change and is expected to change with new researches and time. Some of the researches and factors are discussed below. These are from the research papers that were selected and are not exhaustive and complete by any means.
Alfred article back in 1999 has cumulative factors that were researched on usability . Though it was researched many years ago, it still acts as the basis for various researches on this area. They factors are as follows:
- Tasks: Usability varies with the goal the user intends to perform during the activity. Task on web can be searching information, processing request, reading, writing, navigating etc. It also depends upon the goal with which the web was built for. Usability of a light weight website like static website considers information processing less important than information presentation.
- System Variables: All the software applications are directly or indirectly related to system variables. Web usability is not an exception. The server configuration, user system configuration, internet speed, display capacity of monitor etc. are some of the examples of system variables.
- User characteristics: Web application attracts all kind of user who has access to Internet. The design of website largely depends upon its targeted user group as it is very hard to satisfy all kinds of user. These users can be grouped as an expert or novice, young or old, healthy or unhealthy, able or disable/handicapped, rich or poor, motivated or demotivated etc.
- Searching the web: Website must be easily searched by various search engines like Google, Bing etc. URLs are quite difficult to remember by human brains and people usually search in these search engines for related websites. In a typical scenario, website that gets displayed higher in order is more likely to be referred by users. Thus, it is very important that the web should be displayed on high in order, most preferable on the first page by search engines.
- Web site navigation: Web site navigation is regarded as one of the major common factor in determining usability. The better the navigation the better is the usability. Almost all the website requires user to navigate between their pages for information and to fulfill their goal. It should be easy and quick to navigate between pages. Website with more steps to navigate for information is time consuming, hectic and thus not preferred by user.
- Reading: Almost every user has to read the content of web in one way or another. Web designers have to design in such a way that it is easier to read information, text, instruction etc. It also includes information presentation techniques like graphical presentation, using diagrams and pictures etc. Generally Usability increases with the increase in easiness to read.
- Internet delays: Speed with which information are retrieved to and fro from servers also play a vital role in web usability. Some users might be very sensitive to delays and may avoid using the website. Thus delays should be avoided as much as possible and user should be presented with quick information. Also Internet delays accompanied by data loss impacts heavily on quality of videos and pictures. As stated earlier Nielsen considers the combination of five components: learnability, efficiency, memorability, errors and satisfaction . While Abran et al. enhances his model  and proposes a new model, called as Consolidated Usability Model, which considers efficiency, security, effectiveness, satisfaction and learnability .
Robert and Paul conducted a comprehensively large research; on 36 industrial websites with 400 respondents and 12000 data points with an aim to prioritize web usability factors and predict overall web usability . Though they came to a conclusion that different type of industry has different web usability factors, overall web usability is affected by the following factors in descending order: Use of Color and Font, Clarity of Goals in Website, Trustworthiness of Website, Use of Graphics and Multimedia, Interactivity of Website, Ease of Web Navigation, and Downloading Speed of Website . It states no matter what kind of website, its use of colour and font is the utmost important factor.
4. Web Metrics and its Importance
Many Individuals, nationals and international bodies related to usability and measurements have proposed metrics for web. Some of them are discussed below. There are not exhaustive by any means and many more exists. Also, researches come up with more and better metrics with time.
As stated earlier, Nielsen considers the combination of five components for usability and has proposed metrics for them . He believes measuring those factors with appropriate metrics will play a vital role in analyzing, comparing, contrasting websites. Similarly, Abran et al. also proposes metrics for measurement of his five components in his model, Consolidated Usability Model .
Robert and Paul considers following factors in descending order: Use of Color and Font, Clarity of Goals in Website, Trustworthiness of Website, Use of Graphics and Multimedia, Interactivity of Website, Ease of Web Navigation, and Downloading Speed of Website as the major factors and need to be measured for the success .
ISO (International Organization for Standardization), ISO/IEC (International Organization for Standardization/ International Electro technical commission), IEEE (Institute of Electrical and Electronics Engineer) etc. are some of the international standard bodies that publish standards related to usability . They haven’t proposed a standard that exist true for all website but have many standards, grouped according to type of organization, type of website, target group, platform etc.
Some models like GQM (Goal Question Metric) proposed by Basili are very popular to measure software metrics . The basic idea behind it is that, an organization needs to have a goal that they want to achieve, then questions should be asked in order to find out what is required to accomplish those goals and appropriate metrics should be chosen for their measurement. Basili explains the process in steps where first three steps consist of defining goal, generate questions and define measures that should be taken to answer those questions. The last three steps explain the process of gathering the measured data effectively for betterment and decision making .
Usability is considered as a qualitative attribute that measures the quality of an application . These attributes as discussed earlier are many in number. They need to be measured and each attribute can be measured in various ways. Different ways for measurement for different attributes are proposed by different bodies related to web metrics. Additionally practitioners sometimes use local metrics for their convenience. The bottom line is that factors need to be measured. Also careful examination of attributes and suitable metrics needs to be selected in order to compare, contrast, improve and understand between attributes and web. These metrics will help practitioners develop more effective websites . Project managers and individuals associated with web can understand the relationship between factors and their role in success and can plan accordingly . They are even able to study between similar projects and can find a pattern that can be used as an input for forthcoming similar projects. This all makes people associated with web confident about their work and drastically increases the probability of success of webs.
Even though the study was conducted on relatively small number of literature and the writer experience was only considered, it is evident that web usability is an important area to study. It impacts large population. It is a complex field and there actually exist a number of factors that can impact web usability. These all influencing factors have to be studied in order to analyze, understand, study and improve usability in a long run; this is where software metric comes into picture. But there exist many metrics too. Many individuals, national and international bodies related to software metrics has contributed in the area. But it hasn’t been standard yet. Due to the lack of standardization, practitioners are not able to take the most out it; they are not able to take benefit in large scale from analysis. Standardization should bring the study between projects, companies, within a region or throughout the entire globe. Thus, as also said by many other researchers and practitioners, these measures need to be standardized and a global understanding is to be achieved.
Moreover we also feel that since the domain is very huge, standardization and generalization might not be possible or might not make sense at all, thus it would be a good idea to divide the domain in many sub-domains like web usability in mobile application for European Union which will be pragmatic and make sense too. The subdomains dived should be small but at the same time big enough where practitioners; possibly thousands of them get benefited.
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- ISO. 1998. INTERNATIONAL STANDARD: ISO 924111(Guidance on usability).Geneva.
- Nielsen, J. 1994. Usability Engineering. Boston: Academic Press.
- A. Abran, A. Khelifi, W. Suryn, and A. Seffah, “Consolidating the ISO usability models,” Proceedings of 11th International Software Quality Management Conference and the 8th Annual INSPIRE Conference, 2003.
- Alfred T. Lee: Web Usability: A review of the research.
- Robert J. Nathan, Paul H. P. Yeow: Crucial web usability factors of 36 industries for students: a large-scale empirical study.
- ISO/IEC 9241 Ergonomics requirements for office with visual display terminals (VDTs), International Organization for Standardization, Geneva, Switzerland
- Jonathan W. Palmer: Web Site Usability, Design, and Performance Metrics
- Traynor, Brian: Usability standards – Evolution, access and practice.
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- Software Metrics: A Rigorous and Practical Approach, N. Fenton and S.L.Pfleeger, Brooks-Cole Publishing, 1998