User Interface Evaluation Empirical evaluation Heuristic evaluation - - PowerPoint PPT Presentation

User Interface Evaluation

Empirical evaluation Heuristic evaluation

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When does UI evaluation happen?

Testing and evaluation

Design Development Testing Implementation

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Types of tests

Common to UI and system logic:

▪ Unit testing: individual software components ▪ Integration testing: combined functionality after integration ▪ Functional testing: tests the output in accordance to the requirements ▪ Acceptance testing: customer determines if the software meets all the requirements ▪ Performance testing: performance testing to check the system under load

Specific to UI and UX:

▪ Usability testing: UI friendliness and easy of use ▪ User experience (UX) evaluation: the reactions of the user when interacting with the software

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Types of tests

Unit testing

• Each individual software component is run and tested independently
• Mock up (simulated) data is usually employed
• Usually automated with unit testing tools (eg. JUnit)

Integration, Functional, and Acceptance testing

• The components must be assembled and tested together
• Ideally, the first round of testing must be performed by the development team
• The testers should not be the programmers!
• All bugs should be corrected at this moment
• The final round of testing must be performed by the client

Performance testing

• Automated tools are usually employed to generate extreme loads

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Usability and User experience evaluation

These tests evaluate the user experience using a variety of methods.

Usability: the focus is how well the user can use the system.

• Easiness of use
• Time to complete task
• Number of clicks to complete task
• Number of errors
• …

User experience: the focus is how the user feels when interacting with the system

• Enjoyment
• Motivation
• Intention of continued use
• …

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Methods for UX evaluation

Empirical evaluation

▪ Observation: the evaluator observes the user interacting with the application ▪ Think aloud: participants express their thoughts while executing specific tasks ▪ Remote tests: the evaluator does not directly observe the user, but the observation might

happen through screen sharing or recording

▪ Interviews: the users are interviewed before (expectations) and after (experience) using the

system

▪ Focus groups: a moderator guides a discussion with a group of users (usually carried out after

the users have interacted with the system)

▪ Eye tracking: measuring where the user’s eyes are looking at or eye movement

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Methods for UX evaluation

Observation usability test

https://www.experiencedynamics.com/blog/2015/10/why-attending-live-usability-testing-essential-doing-good-ux

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Methods for UX evaluation

Mobile device observation usability test

http://cruxcollaborative.com/the-challenge-of-mobile-device-usability-testing/

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Methods for UX evaluation

Eye tracking

https://sourceforge.net/p/gazerecorder/eyetracking/2016/02/webcam-eye-tracking-for-usability-testing/

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Empirical usability testing

Participant recruitment:

• Participants have had no involvement in the design or development of the site or product
• They represent a target audience

How many participants?

• Usability tests: at least 5 users
• Quantitative studies: at least 20 participants
• Eye tracking: at least 40 participants

Source: https://www.usability.gov/how-to-and-tools/methods/recruiting-usability-test-participants.html

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Empirical usability testing

Benefits:

• Learn if participants are able to complete specified tasks successfully and
• Identify how long it takes to complete specified tasks
• Find out how satisfied participants are with your Web site or other product
• Identify changes required to improve user performance and satisfaction
• And analyze the performance to see if it meets your usability objectives

Source: https://www.usability.gov/how-to-and-tools/methods/usability-testing.html

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Methods for UX evaluation

Heuristic (expert) evaluation

Inspection of the software by experts (with experience in the field)

▪ Introduced by Jakob Nielsen and Rolf Molich in 1990 ▪ No user participation ▪ Optimal number of evaluators is around 3-5

(check this article on how to calculate the optimal number)

▪ Experts employ a set of design principles or guidelines (the heuristics) to evaluate the UI

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Heuristic evaluation

Nielsen’s usability heuristics:

▪ 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.

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Heuristic evaluation

Nielsen’s usability heuristics: (cont’d)

▪ 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.

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Heuristic evaluation

Nielsen’s usability heuristics: (cont’d)

▪ 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.

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Heuristic evaluation

Gameful Design Heuristics:

▪ Developed by the HCI Games Group at the

University of Waterloo

▪ Targeted at evaluation motivation in software

applications (the app’s potential to afford motivation)

▪ Mainly targeted to be used together with

gameful design methods

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Gameful Design Heuristics

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• Meaningful contribution
• Information and reflection

Purpose and Meaning

• Increasing challenge
• Onboarding
• Self-challenge

Challenge and Competence

• Progressive goals
• Achievement

Completeness and Mastery

• Choice
• Self-expression
• Freedom

Autonomy and Creativity

• Social interaction
• Social cooperation
• Social competition
• Fairness

Relatedness

• Narrative
• Perceived fun

Immersion Intrinsic motivation heuristics

Gameful Design Heuristics

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• Virtual goods
• Incentives
• Virtual economy

Ownership and Rewards

• Status
• Exclusivity

Scarcity

• Urgency
• Loss of rewards

Loss Avoidance Extrinsic motivation heuristics

Gameful Design Heuristics

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• Clear and immediate
• Actionable
• Graspable

Feedback

• Varied challenges
• Varied rewards

Unpredictability

• Innovation
• Disruption control

Change and Disruption Context-dependent heuristics

Summary

▪ Use heuristics evaluation for less expensive and faster UI testing

• With a few expert evaluators, it’s possible to find most usability issues

▪ Use empirical evaluation for more robust and accurate testing

• Testing with potential target users is the only way to have total confidence on the UI’s usability and

the potential user experience

• Choice of technique depends on available resources and type of system being evaluated

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