Human-Computer Interaction & web design

Heuristic Evaluation A heuristic is a guideline or general principle or rule of thumb that can guide a design decision Developed by Jackob Nielson & Rolf Molich.
■ Can be used to evaluate prototypes, storyboards or fully functioning systems Flexible and relatively cheap approach Several evaluators independently evaluate the system for potential problems and identify the possible violations Independent evaluators asses the severity of each usability problem Severity ratings (0-4). 0 – no problem, 1 – Cosmetic problem, 2 – Minor usability problem, 3 – Major usability problem, 4 – Usability catastrophe

Jackob Nielson’s 10 heuristic principles Visibility of system status
- Users should be informed of the progress inside the system through appropriate feedback within reasonable time. When an user perform an action or referring to a continuous process, the status should be clearly visible until the task is completed. Such as progress bar, loading graphics, color change, sound etc.

Jackob Nielson’s 10 heuristic principles Match between system and the real world- The system should speak the user’s language and concepts familiar to the user rather than system oriented terms.

Jackob Nielson’s 10 heuristic principles User control and freedom -The system should provide freedom to navigate and perform action and freedom to undo any accidental actions.

Jackob Nielson’s 10 heuristic principles Consistency and standards-
Users often should not have to wonder whether words, situations or actions mean the same indifferent context. Follow conventions and accepted standards. Submit or send Which one is road winding sign Error Prevention Make it difficult to make errors. A careful design prevents a problem from occurring in the first place. Such as, email non attachment notification, changing password tips Recognition rather than recall–
Make objects, actions and options visible. The user should not have to remember information from one part of the dialog to another. Instructions for use of the system should be visible or easily retrievable wherever appropriate. The goal is to minimize the user memory.

Jackob Nielson’s 10 heuristic principles Flexibility and efficiency of use Allow users to tailor frequent actions. It should be flexible transforming itself between a novice and advanced user. Custom installation or default installation
■ Aesthetic and minimalist design–
Dialogs should not contain information that is irrelevant or rarely needed. Every extra unit of information in a dialog competes with the relevant units of information and diminishes their relative visibility. Google search engine vs. yahoo search engine Help users recognize, diagnose and recover from errors–
Error messages should be expressed in plain language, precisely indicate the problem and constructively suggest a solution. A check needs to be done if exception handling is done across the application so that relevant messages can be shown to the user. Empty state messaging, 404, 500, etc are some examples.

Jackob Nielson’s 10 heuristic principles Help and documentation–
Few systems can be used with no instructions so it maybe 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. Help , FAQ and support pages.

Model based evaluation It using a model of how a human would use a proposed system to obtain predicted usability measures by calculation or simulation. These predictions can replace or supplement empirical measurements obtained by user testing Model-based evaluation can be best viewed as an alternative way to implement an iterative process for developing a usable system.

Other types of evaluation Evaluation through users participation – Laboratory studies, field studies Experimental evaluation – participants, hypothesis, experimental design Evaluation through physiological responses.

Which evaluation methods to choose No hard and fast rules Has its own strengths and weaknesses
Factors distinguishing evaluation techniques The stage in the cycle which the evaluation is carried out
– design vs. implementation, laboratory vs. field studies, subjective vs. objective, quantitative vs. qualitative The style of evaluation
– cognitive walkthrough, heuristic evaluation, model based, review based Required resources
- tools and equipment, time, budget, participants Immediacy of response

Evaluation – Class discussion
Evaluate the following based on cognitive walkthrough and Nielson’s heuristic
principles. What can be improved ??

Evaluating icon design – class discussion
■
Imagine you are designing anew interface to a document-processing package, which is to use
icons for presentation. You are considering two styles of icon design and you wish to know
which design will be easier for users to remember. One set of icons uses naturalistic images
(based on a paper document metaphor, the other uses abstract images How might you
design an experiment to help you decide which style to use?
Natural design
Abstract design
Tips:
Establish hypothesis
Identify variables
Set control of the experiment –
how do you measure?
Establish sample size
Analyze data

UNIVERSAL DESIGN

What is universal design Universal design is the process of designing products so that they can be used by as many people as possible in as many situations as possible It can be achieved by designing systems either to have builtin redundancy or to be compatible with assistive technologies.
Example : a website that provides text alternatives for graphics, a system or application that provides both visual and audio access.

Universal design principles 1990 North Carolina State University proposed 7 design principles, these were intended to coverall areas of design and are equally applicable to the design of interactive systems.

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