Human computer interaction usability

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This paper presents the human computer interaction using the usability of an application through which an human can interact with computer or mechine. There are lots of application for inteacting with human and mechine. Such as image processing, speaker recognition/identification, web applications etc. These application are need to test their usability before they goes to the hand of user. that means how they are effective, whether the user can use it smoothly without any problem, or is there any thing needs to be added for further development of that application. There are several method for usability. We mainly shows and compares two most using method expert usability review and usability testing and also shows some common mistakes which are made by users and some solution also given.

Keyword: human-computer interaction, usability, expert usability review, usability testing


Human computer interaction is an interaction between computer and people, which include both the software and hardware for study, planning and design. A human can interact with computer for various purposes, such as information sharing, daily works etc. Interaction between human and computer is making our life easier and comfortable. We can define human computer interaction in many different ways. Many person give definition of human computer interaction in many different ways [1].

(Hewett et al., 1992): "Human-Computer Interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them".

(Dix et al., 1993):"Human-Computer Interaction is, put simply, the study of people, computer technology and the ways these influence each other. We study Human-Computer Interaction to determine how we can make this computer technology more usable by people".

Preece et al. (1994):"Human-Computer Interaction is about designing computer systems that support people so that they can carry out their activities productively and safely".

By studying Human-Computer Interaction we can learn some supporting knowledge about machine as well as human about different aspects of human actions, motives, capabilities, limitation and also machine capabilities and limitations. The goal of Human-Computer Interaction is to make the system safe and usable by understanding the factors how the people use technology, tools and techniques for making the system effective, efficient and safe interaction. There are different ways for showing Human-Computer Interaction such as graphical user interface, speech processing, image processing, hypertext and multimedia system, usability testing and expert usability reviews etc. We are mainly focuses on usability testing versus expert usability reviews. There are some similarity and dissimilarity between usability testing and expert usability reviews; we will show some review of them where they are similar and where they are conflict with each other. Usability testing is a method, which is used for assess for testing a product by its user. The goal of usability testing is to study the user to discover errors and areas of improvement, the product they are using. Usability testing techniques are basically split into two types: inspection and empirical. Usable interfaces possess five basic attributes [5]:

  • Learnability.- the system is easy to learn. Novice users are able to complete basic tasks in a short period of time, with a minimum of training.
  • Efficiency of use.- experienced users are able to reach a steady state of productivity.
  • Memorability.- the system is easy to remember. Users can return to it after an absence and complete tasks without retraining.
  • Error Prevention.- Users experience few errors while using the system, and recover quickly from them.
  • Satisfaction.- the system is pleasant to use.

Usability testing are basically use for measuring different ways for testing subject areas such as, performance, accuracy, recall and feelings response. Expert usability reviews have a tendency to discover high level breaches of design procedure and reliability. An expert usability reviews is graphical user interface system, such as web site where a specialist inspect can identify the potential usability problem.

Expert Usability Review Vs. Usability testing

Usability is an attribute or charactersitics of every product, just like the functionility. Where the functionility refers to what the product can do. Testing functionility means making sure that the product works according to specification[1]. Usability means focusing on users to develop a usable product. As we will discuss about the expert usability review and usability testing, we are not going deeply to the other part os usablity like evalution or methods etc. The question has come often which method is best- expert usability review or usability tesing?.our discussion basically cover the time, budget, when and how to perform these two test and their advantage and pitfalls, a comparison study. An expert usability review is when a usability specialist inspects GUI or a website to identify potential usability problems. And usability testing involves getting people from the target audience to evaluate your site whilst performing tasks [2]. The goal of both methods is to identify the usability problems in the design so that opportunities for strategic improvements can be uncovered and fixed through an iterative design process.

Expert usability reviews tends to find high level breaches of design rules and consistency. Usability testing is better at finding issues related to special domain knowledge and task flows. If an expert review is carried out before conducting the usability testing and if we comparing the set of findings, maybe there are less possibility to match. There are possibilities in Expert reviews to miss usability issues that arise during usability testing. It may find some issues that usability testing didn't find.

However There is a research conducted by Fu, Salvendy and Turley in 2002 estimated this to be around 41% which shows that there is some overlap in the problems founds in both expert usability reviews and usability testing [2]. Expert usability reviews tend to find more problems compared to usability testing.

In this paper we have shown the differences based on the different criteria-

  • Who conducts the tests (Both Expert review and usability testing)
  • Usability testing is performed by the user after the product (like websites, GUI etc) has released to market. It involves getting people from the target audience to evaluate the product while performing the specific task with that product or application. Usability experts watch the participants performing the task and analyze the needs of user for further development of the application or product. On the other hand expert usability review is solely performed by usability experts. They inspect an application to identify possible or impending usability problem. The experts review the application based on published research, experiences in watching user behavior in the usability lab and design heuristics [3].

  • How many users needed?
  • In usability testing there is no specific numbers of respondents are needed. Usually 5 - 15 participants are enough to find key usability issues. On expert usability evaluation or valuation requires no users. It is the user free method. By using the traditional expert evaluations methodology, it is important to have more than one expert to perform the test. The problem will increase when the number of evaluator increase (Kantner & Rosenbaum, 1997). The ideal no. of expert or evaluator is 2-3.

  • How much would it cost?
  • Usability testing requires more cost as compare to expert usability review. As it needs more time to plan and organize, the preparation of testing protocol, hiring a usability lab, recruiting and incentivizing people from a target user group and conducting tests and analysis is expensive. Usability testing is the most expansive usability evaluation method. In expert review we don't need to hire expensive lab nor recruit users. For this reason the cost are comparatively lower than usability testing.

  • How long does it take?
  • Usability testing is a time consuming process as this method involves detailed protocol scripting, participant recruiting, and conducting the test one by one, followed by data analysis and report generation. Beside this, in expert review, skilled evaluators can produce high-quality results in a limited time. However for a 15-20 people usability test, it is usually takes 4-6 weeks. The time depends upon the complexity of the application in an expert usability review. It is preferred expert usability review to use when time and budget are squeezed.

We have tested some websites as a user and found some potentialities which were missing on expert usability review tests. We have describe those missing issue and try to find out some solution which is found in the usability tests are -

Most of the people has banner blindness, they didn't noticed the banners. Its been found in eye tracking studies their gaze literally avoids settling on any area that looks like an advert instead it seems people actively try to avoid looking at them. This effect is called banner blindness. A good way to avoid banner blindness is to ensure that the sites banner are mostly text, so that they look as much like usefull site content as possiblie.

When people land on a site, they are looking there with a specific task in mind. They won't look at all the other things on the site has to offer. They will be clicking deeper into the site. What ever the developer gives his effor for developing the site has no value. User just want to get their task done. Actuallu its a natural behaviour, we can not do anything on that. But as developer one should beaware of this kind behaviour and ensure that the site's purpose and content are clear. Another common mistakes that people don't take in what they looked at something on a page, it does not mean that they've seen. Often in eye tracking studies it has been shown people hahve looked at something, but they haven't taken it in.

People read very differently while they are online. On the Internet people try not to read untill they feel they are found what they are looking for, until they reach the content they need. That is, people don't read introductory text, instruction text, navigation options etc.anything if they can avoid it. There are several ways to try and reduce the problem- (a)reduce the word count of each page, (b) try to minimize instruction text, (c) highlight key words (d) breakup text using clear sub-headings etc.

People don't like having to learn new ways to do things. Once a user have found a way to do something, he will do it though the other way is the best one. Usually the user won't bother to see if there's a better way unless they find what they do is particularly frustrating. So if a developer would keep that common mistakes while developing a website in mind for the betterment of the site.

The demerits of usability testing is that, it is expensive and time consuming. The validity of test findings depends on identifying the right target group, accuracy of usability testing protocol to recognize key user tasks, and accurate user recruiting. On the other hand, on expert usability review, the problem findings are depends on the reviewer's level of experience. A research, conducted by kantner & Rosenbaum,1997 shows that 43% of the problems that were identified by the heuristic evaluator did not match with the real time user's problem.


Usability testing techniques are generally split into two basic types: inspection and empirical.

Inspection methods are conducted by usability specialists and the product design team, and are useful for identifying major flaws in an interface before users test it. Empirical tests are Conducted with actual members of the target user population. The most important thing is that testing occurs early and often, so that interface problems aren't left for users to find during field tests, when they're most expensive to correct. Usability testing methods are intended to be part of an iterative design cycle, during which the interface design is tested and then redesigned to address issues raised in testing. Usability testing is better at finding issues related to special domain knowledge of users and their task flows. If the usability testing protocol is designed well and covers key user tasks, user testing helps us to find major usability problem. Therefore, in expert usability reviews, heuristic evaluation helps to find minor usability problems. Though heuristic evaluation helps identify some major problems, the number of minor problem still outweighs the major problem. We mention earlier some common mistake in usabilty testing that can be reduced by further research.


Both expert usability reviews and usability testing, have their time and place to use. Expert usability review test are used on the early stage of development and the before the application has to be released to market. But as its says earlier in this article that the expert review will miss some issue that arise during usability testing, and it also reports some false issues. Ultimately the key is to appreciate that expert usability reviews and usability testing are different taste. The most effective approach is to try and integrate both techniques while developing and releasing a product to the real world.