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Requirements and Task Analysis

Requirements and Task Analysis

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Requirements and Task Analysis

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  1. Requirements and Task Analysis

  2. Why are requirements important? • To understand what we are going to be doing • We build systems for others, not for ourselves • Requirements definition: the stage where failure occurs most commonly • Getting requirements right is crucial

  3. Historically requirements Features, functions that the system should do Properties of the overall system “-ilities” (quality, evolveability, flexibility, etc.) Environment User requirements Usability requirements Functional vs. NonFunctional

  4. Not just “requirements” • Overall goals, success criteria • User characteristics • Task analysis • Environment – physical, social, technical • Constraints • Usability goals, criteria

  5. (Not All) Requirements Gathering Methods 1. Observation 2. Thinking Out Loud & Cooperative Evaluation 3. Interviews 4. Questionnaires 5. Focus groups 6. Study Documentation 7. Look at competitive products

  6. Know Thy User • You want to know • Who your users are • What they are doing • When they are doing it • Why they are doing it • What tools they are using • How they are using them

  7. Human Characteristics • Physical attributes(age, gender, size, reach, visual angles, etc…) • Perceptual abilities(hearing, vision, heat sensitivity…) • Cognitive abilities(memory span, reading level, musical training, math…) • Personality and social traits(likes, dislikes, preferences, patience…) • Cultural and international diversity(languages, dialog box flow, symbols…) • Special populations, (dis)abilities

  8. User Characteristics • Attitude, morale, willingness to change, motivation, reading level, typing skill, education, frequency of use, training, color-blindness, handedness, gender,… • Novice, intermediate, expert • System experience, task experience, computer literacy • Cultural factors • Uses of icons, colors, words, metaphors

  9. Design implications • Consider the implications:

  10. Are Cultural Differences Important? Anna: the IKEA agent • Designed to be different for UK and US customers • What are the differences and which is which? • What should Anna’s appearance be like for other countries, like India, South Africa, or China?

  11. Persona: describing users • Description of a user and what the user wishes to do • Put a specific human face on abstract data • Be specific/detailed, even give names and picture • Easier to remember and talk about • Two personas for ATM usage follow • Adapted from User Interface Design and Evaluation, The Open University • Developed by Cooper (1999)

  12. Sandra (representing young adults thru middle age) Sandra is 30, is married to Jason, has two children Todd(6) and Carly (18 months). They live in a subdivision that is about three miles from the town center, where the bank and stores are located. Jason uses the car for work, and works long hours, leaving at 6:45 am and returning at 8:00 pm. Sandra does not drive, so has to use public transportation. She tries to run errands and shop while Todd is in school, so she only has to take Carly to town with her. She typically needs to make two trips to town each week to get everything done. She uses a stroller with Carly, and the bank is one flight up via escalator, so she prefers to use the ATM outside the first floor, even though there is no canopy to protect customers from bad weather.

  13. Grandpa Marvin (representing middle age to senior citizens) Marvin is 68 years old, and his social security is deposited into his bank account at the start of each month. He goes to the bank every week, withdrawing enough cash for the week - for miscellaneous expenditures. Regular bills are paid by check. He stands in line for a live teller, as he prefers the social interaction to using an ATM, even though his new artificial hip makes standing in line uncomfortable. He does not have an ATM card.

  14. Task Analysis • Process of analyzing and documenting how people perform their jobs or activities • Task-subtask decomposition • Focus on: • Activities • Artifacts • Relations • More in a moment…

  15. Physical Environment • Amount of space to work • Lighting levels / directions • Noise level • Temperature, humidity, dust… • Standing / sitting • Power availability • Dangers Implications?

  16. Technical Environment • Computers/platforms for application • Technology to interact with • Networking • Mobility Implications?

  17. Social Environment • How do users interact? Roles? • How do users interact with others? • Social implications of problem or solution? • Interruption • Privacy Implications?

  18. Stakeholders • Primary – targeted end users • Secondary – receive output or provide input to system • Tertiary – others directly receiving benefits from system success or failure • Facilitating – design, development, maintenance

  19. Stakeholder analysis • Cell phone • Bus stop kiosk • Nuclear power plant control system

  20. Typical Real-World Constraints • Elapsed time to market • Cost/effort to design and implement • Size/footprint/weight/power/price • Computer power/memory (related to cost and power • Consistency with overall product line • Backward compatibility • Differentiation from competitive products

  21. Usability Requirements • Usability goals: such as learnability, consistency, robustness, etc. • Ways to measure and judge success • Time to complete key tasks - min, max • Time to become proficient - do given set of tasks in given time • Subjective satisfaction

  22. Example What factors (environmental, user, usability) would affect the following systems? • Self-service filling and payment system for a gas station • On-board ship data analysis system for geologists searching for oil • Fashion website for buying clothes

  23. Example: movie ticket kiosk • List a few user characteristics • Create one persona • List a few important environmental considerations • List a couple other real world constraints

  24. (Not All) Requirements Gathering Methods Observation Thing out Loud & Cooperative Evaluation Interviews Questionnaires Focus groups Study Documentation Look at competitive products Ethnography Contextual Inquiry

  25. Summative assess an existing system judge if it meets some criteria Formative assess a system being designed gather input to inform design Summative or formative? Depends on maturity of system how evaluation results will be used Same technique can be used for either Formative vs. Summative evaluation

  26. Observation • Watch user(s) doing activity of interest to you • “Think out loud” or “Think aloud” • encourage user to verbalize what they are thinking • Cooperative or participative evaluation • Relaxed version of think-aloud • Evaluator and user talk to each other • Why are you doing that? • How did you know the result was what you wanted? • Are there other ways to achieve the same goal? • How did you decide to do things this way?

  27. Observing Tips • Carefully observe everything about users and their environment • Think of describing it to someone who has never seen this activity before • What users say is important, so are non-verbal details

  28. Interview Users • Semi-structured: predetermine sets of questions • But can expand upon them as needed • Example question types • How do you perform task x? • Why do you perform task x? • Under what conditions do you perform task x? • What do you do before you perform…? • What information do you need to…? • Whom do you need to communicate with to …? • What do you use to…? • What happens after you…? • What is the result or consequence of…? • What is the result or consequence of NOT…? See DFAB 9.4.4 for more tips and discussion

  29. Focus Groups • Interview groups of users – 3 to 10 at a time • Use several different groups with different roles or perspectives • Relatively low cost, quick way to learn a lot • Use structured set of questions • More specific at beginning, more open as progresses • Allow digressions before coming back on track • More challenging to lead than single interview • Some people quiet, some dominating • Easier to get off track

  30. Questionnaires (or Surveys) • Easier to give to broader audience • Shorter, more focused than interview • General criteria • Make questions clear and specific • Ask some closed questions with range of answers • Sometimes also have a no opinion option, or other answer option • Do test run with one or two people

  31. Some Example Questions • Rank the importance of each of these tasks (give a list of tasks) • List the four most important tasks that you perform (this is an open question) • List the pieces of information you need to have before making a decision about X, in order of importance • Are there any other points you would like to make? (open-ended opinion question; good way to end) • Numerical scales: On a scale of 1 to 7, how comfortable are you… Or words: Strongly agree, agree, neutral, disagree, strongly disagree

  32. Example: movie kiosk • What to observe? How? • Who to interview? What questions? • Who to give questionnaire to? What questions? • What about focus group? • What are differences between methods?

  33. Study Documentation • Quick and easy if it exists • Often describe how things should be done rather than how they are done • Try to understand why not done “by the book” • Alternative: interview a domain expert

  34. Look at Competitive Products • Looking for both good and bad ideas • Functionality • UI style • Possibly do user task performance metrics to establish bounds on your system

  35. Ethnography • Deeply contextual study • Immerse oneself in situation you want to learn about (has anthropological and sociological roots) • Observing people in their cultural context • Behavior is meaningful only in context • For UI designers: understand current methods, activities, environment, problems to aid design • Observation + interviews

  36. Ethnography • Things of interest to evaluator • Structure and language used in work • Individual and group actions • Culture affecting work • Explicit and implicit aspects of work • Example: Office work environment • Business practices, rooms, artifacts, work standards, relationships between workers, managers, …

  37. Drawbacks of Ethnographic Methods • Time required • Can take weeks or months for large systems • Scale • Most use small numbers of participants just to keep somewhat manageable • Type of results • Highly qualitative, may be difficult to present/use • Acquired skill – “learn by doing” • Identifying and extracting “interesting” things is challenging

  38. Contextual Inquiry • Practical ethnographic-inspired method for requirements • Master-apprentice relationship • Watch and talk to customer as they do their work • Designer looking for details and structure of work that will influence design • Contextual interview + observation

  39. Contextual Inquiry Principles • Context • Gather information close to real situation • Avoids abstractions and summarization • Partnership • Designers help customers see and talk about structure through probing • Share design ideas in the moment • Interpretation • Designer must turn observations into useful design implications • Share this reasoning with customer to get feedback • Focus • Designer must focus on aspects of work that will be useful For more info: see Beyer and Holtzblatt. Contextual Design. Morgan Kaufmann.

  40. Contextual Inquiry • How compares with other methods? • Advantages? • Disadvantages? • In what situations would it be useful? • When might it not be useful?

  41. Which Methods to Use? • Self-service filling and payment system for a gas station • On-board ship data analysis system for geologists searching for oil • Fashion website for buying clothes at large department store

  42. Making Sense • Organize and categorize responses, comments, observations • “coding scheme” • Card Sorting • Affinity Diagrams • Task analysis

  43. Affinity Diagram - “Sorted Cards” From Interaction Design, Preece Rogers and Sharp

  44. Task Analysis • Focus on observable behaviors • What are the practices, methods, steps, objects, …, used? • Tasks & Subtasks • Physical • Cognitive • Communication • Conditions under which these tasks are done • Results/outcomes of tasks • Requirements to perform task • Information, artifacts • Communication with others • Equipment Also see: Hackos and Redish, User and Task Analysis for Interface Design. Wiley Publishing.

  45. Describing activities • Scenarios • Use Cases • Task - subtask decomposition • Includes sequencing information • Workflow diagrams • Flow charts • ER or object models

  46. Scenario • Describe tasks and context in sentences • Natural way of describing general idea • Good for demonstrating specific problems, reasons behind actions, atypical activities • Bad for representing branching, parallel activities, various possibilities of one activity

  47. Scenario: Example 1 • Its Friday afternoon and John just got paid. He wants to deposit his check immediately so he can pay his rent. He stops at one branch of his bank on the way home from work. He waits in his car while another person finishes using the ATM in front of the bank since it is drizzling outside. He walks up to the ATM to deposit his check. Only, as he is about to put the check into the envelope at the ATM, he realizes that he has not signed the back of it, and he has no pen and can not find one on or near the ATM machine. He cancels the transaction on the ATM, and enters the bank, which luckily is still open for 5 more minutes. He goes to the counter, finds a pen, and signs his check. He also fills out a deposit slip. He then waits to see a teller in person to deposit his check, and get money for the weekend.

  48. Scenario: Example 2 • Annie walks up to the ATM to deposit her weekly pay check. She puts her ATM card into the slot in the machine. She then enters her PIN number quickly, trying to block the person waiting behind her from viewing the keypad, and knows that she does not have to press “Enter” at this particular machine. She then chooses “Deposit” and “Check.” She enters the amount of the check using the keypad, then takes an envelope from the ATM machine, puts her check inside, seals the envelope and writes the amount of the check on the outside. She feeds the envelope into the slot into the ATM machine. She then selects “No other transactions” to finish, and waits to receive her receipt and ATM card.

  49. Use Case • Description of a user’s goal in using a system • Focuses on user-system interaction • One path through a use case is sometimes called a scenario • Often presented as a series of steps • Diagram of actors and use cases

  50. Use Case Diagram