USABILITY -
By Priti Gadgil
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Contents Usability ..................................................................................................................................................................................... 4 Characteristics of Usability .................................................................................................................................................... 4 Effectiveness ...................................................................................................................................................................... 4 Efficiency............................................................................................................................................................................ 4 Engaging ............................................................................................................................................................................ 5 Error Tolerant .................................................................................................................................................................... 5 Easy to learn ...................................................................................................................................................................... 5 Usability Evaluation Methods.................................................................................................................................................... 5 Testing method.......................................................................................................................................................................... 6 In lab testing .......................................................................................................................................................................... 6 Thinking aloud Protocol..................................................................................................................................................... 6 Tree Testing ....................................................................................................................................................................... 7 Remote Usability testing ....................................................................................................................................................... 8 Prototyping method .................................................................................................................................................................. 8 RITE method .......................................................................................................................................................................... 9 Paper Prototyping................................................................................................................................................................ 10 Card Sorting ......................................................................................................................................................................... 10 Storyboarding ...................................................................................................................................................................... 11 Inspection method .................................................................................................................................................................. 12 In-lab inspection .................................................................................................................................................................. 12 Cognitive walkthrough .................................................................................................................................................... 12 Pluralistic walkthrough .................................................................................................................................................... 13 Cognitive modelling ......................................................................................................................................................... 13 Ethnographic testing ........................................................................................................................................................... 14 Heuristic evaluation............................................................................................................................................................. 15 Neilson’s 10 heuristics for user-interface design ............................................................................................................ 15 Inquiry method ........................................................................................................................................................................ 17 Focus Groups ....................................................................................................................................................................... 17 Interview/survey ................................................................................................................................................................. 17 Other methods .................................................................................................................................................................... 18 Benchmarking .................................................................................................................................................................. 18 Meta-analysis .................................................................................................................................................................. 19 Persona ............................................................................................................................................................................ 19 Problems with Usability Evaluation Methods ......................................................................................................................... 20 Usability lab testing ............................................................................................................................................................. 20
Inspection method .............................................................................................................................................................. 20 Inquiry method .................................................................................................................................................................... 20 Steps to conduct a usability test.............................................................................................................................................. 20
Usability
- Ease of use and learnability of an object. - A product should be manufactured from the user’s point of view. - ISO defines usability as "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." Usability engineering: research and design process that ensures a product with good usability. Usability testing: measurement of ease of use of a product or piece of software.
- Goal of a technical writer: produce technical documentation that can be clearly comprehended by all sorts of users. o Promotes Effective learning(fit for the purpose) o Increases Efficiency of learning(time to learn is less) o Engaging o Error tolerant o Easy to learn
E FF E C T I V E N E S S
- completeness and accuracy with which user can achieve the specified goal - is determined by looking at whether the user’s goals were met successfully and whether all work is correct - shows how well the work is done - tech docu should enable the user to use the product to its maximum capacity. E FF I C I EN CY
- manner in which the task is performed
- speed and accuracy with which goal is achieved - total number of resources expended in a task E N G AG IN G
- user should be naturally attracted and pleased to use the document - important factors to make a document engaging: o visual presentation, images and animation
E R RO R T OL E RA N T
- robustness : how tolerant the system is of user error o document should consider all cases of possible error by the user - recoverability: how good the system is at recovering from user error o document should give ways to the user to recover from errors made.
EASY
T O L E ARN
- User should find it easy to use the document and to build on prior knowledge - Document pattern should be predictable
Usability Evaluation Methods
- There are different categories of evaluating usability of a document/product: 1) Testing 2) Inspection 3) Inquiry 4) Prototyping - Each method has a unique advantage and functions within the entire development process. - Each method collects different types of data
TYPES OF DATA COLLECTED o Performance/preference data ▪ Performance data : when user performs a task ▪ Preference data: when user adds questions o Objective/Subjective data ▪ Objective data: user data: eg. Time taken to complete task ▪ Subjective data: user’s interpretation o Qualitative/quantitative data ▪ Quantitative data: eg:no. of tasks completed correctly ▪ Qualitative data:eg. Type of response: positive/negative
Testing method
- Process of gathering qualitative and quantitative feedback from users - Usually recorded on video, they provide task completion time and allow for observation of attitude. - Usability tests involve typical users using the system (or product) in a realistic environment - After conducting usability tests, it is important for a designer to record o Record what was observed and why such behaviour occurred o modify the model according to the results.
T H I N K IN G
A LO U D
P R O TO C OL
- In-lab test - User expresses thoughts on the application while executing the set task - Useful for finding design flaws that do not affect task performance, but may have a negative cognitive effect on the user. - it can provide insight into the user's attitude, which cannot usually be discerned from a survey or questionnaire.
T R E E T E ST I N G
- Users are given ‘find it’ tasks - Reverse card-sorting - To evaluate the effectiveness of a website structure in terms of o the findability of content o visual design - helps to determine how to organize the content of a website - A large website is typically organized into a hierarchy (a "tree") of topics and subtopics. Tree testing provides a way to measure how well users can find items in this hierarchy. - Unlike traditional usability testing, tree testing is not done on the website itself; instead, a simplified text version of the site structure is used. o ensures that the structure is evaluated in isolation, nullifying the effects of navigational aids, visual design, and other factors.
- user testing is conducted on multi-platform and multi-screen (computer, phone, tablet) - involves the use of a specially modified online survey - this style of user testing also provides an opportunity to classify feedback as: demographic, attitudinal and behavioural type. - The tests are carried out in the user's own environment (rather than labs) helping further simulate real-life scenario testing (background noise, office or home interruptions, highly customized workstation setup) and eliminating the need for dedicated facilities. - effective way to learn about the problems the users face with the product.
Prototyping method
- quick and cheaply way to evaluate user-interface designs without the need for an expensive working model. - It is often very difficult for designers to conduct usability tests with the exact system being designed. - Cost constraints, size, and design constraints usually lead the designer to creating a prototype of the system. - Instead of creating the complete final system, the designer may test different sections of the system, thus making several small models of each component of the system. - used in early stages of development to validate and refine the usability of a system. - can help remove hesitation to change the design, since it is implemented before any real programming begins - Advantages of Prototypes: o able to be modified quickly
o often are faster and easier to create with less time invested by designers o are more apt to change design - Disadvantages of Prototypes: o not an adequate representation of the whole system o are often not durable o testing results may not be parallel to those of the actual system.
- Rapid Iterative Testing and Evaluation (RITE) - In-lab test - The tester and team must o define a target population for testing, o schedule participants to come into the lab, o decide on how the users behaviours will be measured, o construct a test script and have participants engage in a verbal protocol (e.g., think aloud). - changes are made to the user interface as soon as a problem is identified and a solution is clear. - The changed interface is then tested with the remaining users.
- Inexpensive, rapid, very productive - Uses only paper, scissors and sticky notes - Use one piece of paper for each Web page you create and then have users try them out in a usability test. - Users indicate where they want to click to find the information and you change the page to show that screen. - The process helps you to gather feedback early in the design process, make changes quickly, and improve your initial designs.
- A group of users is guided to generate a category tree - The concepts are first identified and written onto simple index cards or Post-it notes. - The user group then arranges these into different categories. - The way that the items are organized should make sense to the target audience - useful for designing information architecture, workflows, menu structure, or web site navigation paths.
- helps understand users' expectations and develop better understanding of content. - this technique is used to o Build the structure for a website o decide what to put on the homepage o Label categories and navigation
- Prototype consisting of a series of screen sketches - Used by designers to illustrate, organize their ideas and get a feedback - Advantages: o Provides an overview of the system o Demonstrates the functionality of the storyboard elements o Demonstrates the navigation scheme o Can check whether the presentation is accurate and complete o Can be evaluated by users. o Saves time and money
Inspection method
- This method involves observation of user by the expert
COGNITIVE
W A L K TH R O U G H
- User browses through the UI and provides feedback to designer - Evaluate understandability and ease of use of the product - Useful in understanding the users’ thought process and decision making during exploratory browsing.
P L U R AL I S T IC
W A L K T H R O UG H
- A team of users, usability engineers and product developers review the usability of the paper prototype of the application. - Usability issues are resolved faster - Greater number of problems can be found at one time.
COGNITIVE
MO D EL L I N G
- Create a computational model to estimate how long it takes for people to perform a given task. - This cognitive model is used to: o Determine time for cognitive processing and motor movement o Predict problems o Pitfalls in design
- Inspection of people or citizens’ lifestyles, behaviour and attitudes. - Involves o observation of people in their usual environment o interviews to collect personal comments about how they feel. - Benefits o Helps understand the people in their own context, their daily lives, lifestyles, social relationships, behaviours and attitudes, how they use the technologies and their real surroundings. o reveals design solutions that are based on real user interactions and experiences (this technique moves beyond the technical specifications of the product).
o develop empathy. It is an opportunity to put oneself in the person’s situation and experience the world as they do (i.e. to see what they see, to feel what they feel, to hear what they hear).
- involves evaluation of usability of a product by a usability specialist - Usability specialist checks if each dialog box follows usability principles or not. - Intuitive evaluation method
N E I L S ON ’ S 10
H E U R I S T I C S F O R U S E R - IN T ER F AC E D E S IG N
1. Visibility of system status: o The system should always keep users informed about what is going on, through appropriate feedback within reasonable time. 2. Match between system and the real world: o The system should speak the user's language, with words, phrases and concepts familiar to the user, rather than system-oriented terms. o Follow real-world conventions, making information appear in a natural and logical order. 3. Consistency and standards: o Users should not have to wonder whether different words, situations, or actions mean the same thing. o Follow platform conventions. 4. Aesthetic and minimalist design: o Dialogues should not contain information which is irrelevant or rarely needed.
5. Flexibility and efficiency of use: o Allow users to tailor frequent actions. 6. Help and documentation: o Even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. o 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. 7. Recognition rather than recall: o Minimize the user's memory load by making objects, actions, and options visible. o The user should not have to remember information from one part of the dialogue to another. o Instructions for use of the system should be visible or easily retrievable whenever appropriate. 8. User control and freedom: o 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. o Support undo and redo. 9. Error prevention: o Even better than good error messages is a careful design which prevents a problem from occurring in the first place. o Either eliminate error-prone conditions or check for them and present users with a confirmation option before they commit to the action. 10. Help users recognize, diagnose, and recover from errors: o Error messages should be expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution.
Inquiry method
- This method involves field observation – go to the users’ place and observe how they use the system. - Learn about users’ needs of the system through: o Observation o Verbal questioning o Written questioning
- abt 6-9 users are brought together to discuss issues relating to the system - A moderator guides a discussion with a group of users of the application - If done before prototypes are developed, can save money - Produces a lot of useful ideas from the users themselves - Can improve customer relations
- user is interviewed to find out about their experience and expectations - Good at obtaining detailed information
- Few participants are needed - Can improve customer relations
B E N C H MA RK I N G
- compare one’s business processes and performance metrics to industry bests and/or best practices from other industries (benchmarks) - Dimensions measured: quality, time and cost. - Improvements from learning mean doing things better, faster and cheaper - Creates std test material for a specific type of design - Once there is a benchmark, other designs can be compared to it to determine the usability of the system.
M E T A - AN A LY S I S
- combine findings from multiple/independent studies - Used in medical research: o to assess the clinical effectiveness of healthcare interventions; it does this by combining data from two or more randomised control trials o this provides a precise estimate of treatment effect
. P E R S ON A
- A persona is a representation of a fictitious user that includes a concise summary of characteristics of the user, their experience, goals and tasks, pain points, and environmental conditions. - Personas describe the target users of a tool, site, product or application, giving a clear picture of o how they're likely to use the system, and o what they’ll expect from it. - By designing an interface to meet the needs of specific personas, the needs of wider groups of users with similar goals are met. - Also known as user profiles, user role definitions, audience profiles. - Personas are usually created at the start of a development, or redevelopment process.
Problems with Usability Evaluation Methods
- Additional resources and time are required compared to the other methods - Test scope is limited to the sample tasks chosen. Therefore, only a fraction of the entire market segment is examined. - Problems are difficult to identify. Therefore, only a fraction of the total problems may be revealed. - Lab setting – different from actual user environment
- Do not usually directly involve users and developers - This method is used to determine problems – not solutions
- Survey method: small sample size (10 or lesser persons) is usually not reliable - Interview: length of interview makes one use smaller sample size - Field method: needs extensive planning, recruitment and execution
Steps to conduct a usability test
Plan
Conduct Analyse and report
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Define what to test Define how to test/ test scenario/create a test plan Set up test environment Select participants Conduct the test Collect the data Compile result Make recommendations
Example: Website
