Introduction on Usability

Transcription

1 Introduction on Usability Courtesy of Luca Triacca TEC-Lab University of Lugano Agenda Introduction on Usability MiLE+: a systematic method for usability evaluation 2 1

2 Usability Foundations: an Introduction Usability within the lifecycle A interactive application is conceived by a variety of stakeholders for a variety of objectives addressed to a variety of users enabling them to accomplish a variety of goals Proper management of the lifecycle is key to the success of the application. 4 2

3 Usability within the lifecycle Requirements management Design Implementation Content management Evaluation Promotion & Change management Maintenance & Enhancement 5 User Experience Lifecycle / 1 Requirements management Design Understanding user needs motivations and goals Implementation Shaping the user experience Content management Evaluation Assessing the user experience Promotion & Change management Creating awareness & motivations Maintenance & Enhancement Instilling motivations to re-visit 6 3

4 User Experience Lifecycle / 2 Pervasive Usability (Brink et al.:2002) Requirements analysis Conceptual design Mockups & prototypes PRODUCTION LAUNCH EVALUATION 7 Our vision on Usability To be successful, Interactive Applications (being them available on web, palm, kiosks, or a combination of them) have to be USABLE. Usability is an essential factor for a successful user experience: Being it learning, studying, deciding, visiting, enjoying or being entertained through an interactive application An interactive application is usable if Usability ROI are: Lower customer calls for assistance Brand equity enhancement Trust building... Example of poor usability:

5 Understanding Usability Application-independent usability aspects: understandability. navigation quality content accuracy consistency application status communication graphic and layout quality interface order. compliance with standards and conventions...accessibility These features can be evaluated even without knowing the purpose and the user of the application 9 Understanding Usability Application-dependent usability aspects: Users can achieve their goals People find the information they need... People are properly driven and guided to unexpected content.. Content is relevant to specific user profiles (kids, local tourists, tourists from abroad, families, curious, )... Content is enjoyable/entertaining for specific user profiles.. The application can be effectively used in a specific context (while driving, while at home, office, walking, visiting, ) Understanding users, their goals and the contexts of use is essential to evaluate these features. 10 5

6 Understanding Usability From ISO : Usability is the effectiveness, efficiency and satisfaction with which specified users can achieve specified goals in particular environments. The effectiveness of application-independent aspects (font, layout, navigation, structure, ) is a necessary condition for usability The effectiveness of application-dependent aspects (meeting user profiles, context, needs and goals) is a necessary condition for usabilty 11 Understanding Usability Usability evaluation should be done as early as possible in the development cycle: The later errors/problems/flaws are discovered the more is expensive to fix them Anticipate breakdowns and errors on design artifacts It should assess the effectiveness of what is there and not inquiry about what is missing 12 6

7 State of the Art Approaches to evaluate usability: Who measures usability? User Testing (or Empirical testing) Users are the measure of quality Inspection Expert review How to measure it? Task-oriented (scenario-based) Doing things with the application Heuristics Verifying compliance with usability principles 13 Usability Evaluation Methods_1 Empirical testing: involves some representative users evaluators collect usability data from users simulating a session of use Problems: gap btw real sessions and simulated ones the problem of representative users effective for detecting impact of overall look&feel high costs Main techniques: Thinking aloud Contextual inquiry Focus group 14 7

8 Usability Evaluation Methods_2 Inspection methods: involve usability experts ONLY evaluator systematically performs tasks on the application effective for detecting usability and design errors and breakdowns analytic, repeatable, at lower costs than empirical testing Drawback: may neglect or underestimate some problems Main techniques: Heuristic evaluation (Pluralistic) Walkthrough

9 Usability Evaluation Methods_3 It is empirically proved that the most effective evaluation (i.e., the highest amount of usability problems discovery) is achieved by systematically combining evaluation and empirical testing 17 usability perspectives and dimensions of analysis PERSPECTIVES: Technical or application independent : The aspects that are independent from the nature of the specific application an its user requirements Application dependent: The aspects that can be judget only in relationship to the nature of the application a the actual user requirements DIMENSIONS OF ANALYSIS corresponding to different design dimensions. In web applications, for example: NAVIGATION CONTENT OPERATIONS DIALOGUE/SEMIOTICS GRAPHIC & LAY-OUT TECHNOLOGY 18 9

10 Examples of Application independent Usability Problems 19 Content 20 10

11 Currency of Information Page visited the 2th December 21 Technology/Performance 22 11

12 Browser Compatibility Explorer 6.0 Mozzilla Firefox Semiotics 24 12

13 Understandability of the main menu 25 Cognitive 26 13

14 Information Overload 27 Graphic Technical 28 14

15 Background Contrast & Font size Are you able to read the different information on the screen? 29 Navigational 30 15

16 Backward Navigation? 31 Examples of Application dependent Usability Problems 32 16

17 Concept of scenario User/Customer Experience End-user Want to do something Through a series of acts Web usage Users profile Goal Tasks SCENARIO Which are to be evaluated Evaluation activity SET OF USER EXPERIENCE INDICATORS USABILITY KIT (U-KIT) 33 User Experience Inspection / 2 How to create scenarios Interaction with stakeholders and end-users Visioning techniques UEIs: tools for evaluating scenarios Three categories of UEIs (corresponding to the different types of user interaction experiences) Content Experience Indicators Navigation & Cognitive Experience Indicators Interaction Flow Experience Indicators 34 17

18 Examples of Content Experience Indicators SCENARIO USER PROFILE GOAL TASKS Well-educated American tourist who knows he will be in town, he wants visit the real museum on December 6th 2004 and therefore he/she would like to know what special exhibitions or activities of any kind (lectures, guided tours, concerts) will take place in that day. Tourist Visit the M useum in a specific day Find the events/exhibitions/lectures occurring on December 6th in the real museum Find information about the museum s location UEIs: - Multilinguisticity - Satisfaction on provided information 35 Multilinguisticity I m an American tourist. It does not exist the English version of the current exhibition s description? And the description of the collection?

19 Examples of Navigation & Cognitive Experience Indicators SCENARIO USER PROFILE GOAL TASKS Marc looking for some information about Enlightenment period studying at school. Marc, High-school student To be informed on a specific historical period (e.g. Enlightenment) Find general information about this period; Find detailed information about social and religious impact of Enlightenment period. UEIs: - Links Predictability - Memorability of online tours 37 Links Predictability What happens when I click on the button Tours? And on the button Take a online tour? Which is the difference?

20 Examples of Interaction Flow Experience Indicators SCENARIO USER PROFILE David looking for some information about special projects actually presented in the museum. Contemporary Art lover GOAL To be informed on special projects TASKS Find general information about special projects; Find detailed information about a specific project (The Uncertain Museum). UEIs: - Naturalness - Engagement 39 Naturalness How the navigation between objects works?

21 Engagement Once understand the interaction strategy of the website, this could be entertaining MiLE+ Method: short introduction Developed in cooperation between HOC-Lab (Politecnico di Milano) and TEC-Lab (University of Lugano). MiLE+ (Milano-Lugano Evaluation) strikes a healthy balance between heuristic evaluation and task-driven techniques. Offers reusable tools and procedures to carry out both inspection and user testing within budget and time constraints. Two types of Inspection activities: Technical Inspection For discovering application-independent problems User Experience Inspection For discovering application-dependent problems 42 21