Study On Usability And User Interface Design Computer Science Essay

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This report is mainly related with the usability and focuses on presenting and discussing different methods of usability and factors which makes usability unreliable. In market-driven software development it is very important to produce the best product as soon as possible to gain customer satisfaction, therefore requirement arrive at a high rate and the main focus tends to be on the functional requirements. No doubt that functional requirement is very important but their usefulness relies on their usability. Existing methods helps software development companies to improve the usability of the product, but when the companies have little experience in usability still find it to be difficult to use, unreliable and more expensive than normal.


Usability is a general term that surrounds everything having to do with how much the product is easy to use. That is, how easily people can use any product's controls or displays such as tools, computer display, automobile, aircraft etc. Usability also refers to the study of methods, measurement, and principles of product to make it efficient, easy to use and useful. In the computer industry, usability often refers to the ease in terms of the human-computer interaction. The clarity, intuitiveness, seamlessness and elegance of an application or website interface design.

The main idea behind interface is to design products with the user in mind and also the complete requirement of the user, because putting the user first in the user design process can achieve great efficiency and user satisfaction, and this process is normally known as optimized user experience.

Now for achieving optimized user experience it requires a systematic approach to usability while designing such interfaces and this is done through expert usability testing where experts are observed to determine what the design works and what does not work to fulfill user requirements. Changing the design parameters to accommodate the changes gained from user testing permits an optimized user interface design.

The goal of the optimized usability is to make a product easy to understand, easy to use, easy to learn and also easy to interact with. The result of good usability is a greater likelihood of user acceptance, and the changes made after the result of the usability test can easily be incorporated in design process, because the user acceptance is very much important while developing such interactive designs, and user acceptance is often the difference between a product's success and failure in the marketplace. Sometime users can reject a well engineered product with great functionality if users are unable to understand, learn and easily use that product.

When to perform usability test

Usability test mainly focus on the performance of the user interface design so it let the design and development team identify problems before actual coding starts, so find design problems as soon as possible is good to develop efficient and user satisfied product. The early those problems are found and fixed before coding the less expensive and less time consuming process will be [4].

There is no need of special lab for usability test; usability test can be performed effectively in any of the following setup,

A conference room, user work space user's home.

Usability test can be performed remotely with the user in a different location.

Lab having two or three connected rooms having audio and visual setting.

Is usability unreliable

Reliability of usability test is a problem because of the huge individual differences between test users [7].Usability evaluation is best method for many products, but to determine what team priorities should be is not one of them, there are some points which should be keep in mind while doing usability evaluation and avoid these points to make usability evaluation reliable.

Wrong People Selection

There are different people used in evaluation methods and different teams get different results because evaluation and testing are often poorly performed, sometime usability evaluator ask right questions from wrong persons and there evaluator gets incorrect information and evaluation become unreliable.

Usability evaluation Criteria's

Usability evaluators are highly professionals and they have expertise in their field, they have skills, degree of talent and information how to implement different skills in different place while performing usability evaluation, and they have prepared different heuristics [2] which they are using in different situations. But whenever new people are using these heuristic they don't have complete information of this they get some different results. Anyone can use and perform heuristics does not mean that it will produce the same useful result. Heuristics are baseline for usability evaluator not a checklist [6].

Usability testing without context

Context of the test should be cleared to user who is take part in test, because without proper knowledge and information about the design user cannot get into the real understanding of the test. Users should not be in doubt while performing usability test, lack of information may responsible for unreliable result.

Heuristic evaluation

A heuristic evaluation is a usability inspection method for computer software which can be used to find usability problems in the user interface design. It mainly involves evaluator to examine the interface and judge its compliance with recognized usability principles.

"In heuristic evaluation experts go through the interface and inspected the behavior of the software [1]. The behavior is compared to the meaning and purpose of set of ten guidelines called heuristics that focus on the central and most important aspects of usability, such as 'user control and freedom' and 'flexibility and efficiency in use'. This enables the evaluator to systematically check the software for usability problems against actual requirement in the specification and given features in the product. Then a list is composed to identify the usability problems that may be used to improve the software performance''.


These are ten general principles for user interface design [2]. They are called "heuristics" because they are more in the nature of rules of thumb than specific usability guidelines.

''Visibility of system status

The system should always keep users informed about what is going on, through appropriate feedback within reasonable time.

Match between system and the real world

The system should speak the users' language, with words, phrases and concepts familiar to the user, rather than system-oriented terms. Follow real-world conventions, making information appear in a natural and logical order.

User control and freedom

Users often choose system functions by mistake and will need a clearly marked "emergency exit" to leave the unwanted state without having to go through an extended dialogue. Support undo and redo.

Consistency and standards

Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow platform conventions.

Error prevention

Even better than good error messages is a careful design which prevents a problem from occurring in the first place. Either eliminate error-prone conditions or check for them and present users with a confirmation option before they commit to the action.

Recognition rather than recall

Minimize the user's memory load by making objects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another. Instructions for use of the system should be visible or easily retrievable whenever appropriate.

Flexibility and efficiency of use

Accelerators -- unseen by the novice user -- may often speed up the interaction for the expert user such that the system can cater to both inexperienced and experienced users. Allow users to tailor frequent actions.

Aesthetic and minimalist design

Dialogues should not contain information which is irrelevant or rarely needed. Every extra unit of information in a dialogue competes with the relevant units of information and diminishes their relative visibility.

Help users recognize, diagnose, and recover from errors

Error messages should be expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution.

Help and documentation

Even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. Any such information should be easy to search, focused on the user's task, list concrete steps to be carried out, and not be too large.


The method can be used for some fast and relatively inexpensive feedback to designer, the main advantage of this method is that feedback can be obtained early in the design process. Assigning the correct heuristic can help the best corrective measures to designer. Heuristic method is intuitive and easy to motivate potential evaluators to use the method, for this method no advance planning is required to carry out heuristic testing''.


Heuristics methods requires a certain level of knowledge and experience to apply the heuristics effectively, sometime it is hard to find trained usability experts and it can be expensive. Sometime the evaluation may identify more minor problems and fewer major problems.

Individual interviews

Individual interviews typically refer to talking with one user at a time, face to face, by telephone, with instant messaging, Skype or other computer aided medium for communicating with user. This individual interview does not involve observing a user directly while working but you can probe their attitude, belief, desires, and experiences, in this interview user is asked to rate and rank choices for user interface content.


As individual interview is one to one based information taken from user, because of its one to one nature it is very easy to judge what is talked about. Mistakes and misunderstanding can be easily and quickly identified and removed.


Although individual interviews give you exact mental approach of an individual user, but sometime it does not provide access to reality, then there will be a gap between what one says and what one does. Individual result cannot be applied to wider community because the result from individual result is not the representation of the whole community.


Usability is not an unreliable evaluation method but there are some factors that make it unreliable and it is obvious that no every team or any organization can afford the expenses of usability test, but at last one can do what is most suitable and feasible in particular environment. If evaluation is an option, be sure to use the tools for right person at right time and for right job and be sure to approach the process with clear expectation.