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CS2341

CS2341. Lecture 4 Gathering User Requirements Robert Stevens. Introduction. Making models of users Gathering initial information Questionnaires The UML process Interviews. Gathering Requirements. Talking to users and thinking hard We need consistency, replication and recording

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CS2341

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  1. CS2341 Lecture 4 Gathering User Requirements Robert Stevens CS2341

  2. Introduction • Making models of users • Gathering initial information • Questionnaires • The UML process • Interviews CS2341

  3. Gathering Requirements • Talking to users and thinking hard • We need consistency, replication and recording • Use a methodology • Various kinds of technique: • Soft System Methodology • Socio-technical models • Participatory design • UML’s own flavour CS2341

  4. Basics of Requirements Gathering • Talk to users and ask what they do and how they do it • A difficult task • Questionnaires • Interviews • When systems already exist • When systems do not exist at all • Situated cognition CS2341

  5. Business Process • Business processes are graphs of activities that carry out some meaningful business operation. • Purchasing an airline ticket, managing inventory in a warehouse, and ordering furniture for a home or office • You will model business processes • How human and artefacts use and are used in a business process CS2341

  6. Questionnaires • Used for remote users • Paper or electronic forms • Easy to administer • Poor quality, superficial information • Good for overviews • Good for simple quantitative information: Kinds of drinks consumed CS2341

  7. Questionnaires (2) • Internal questions: What you wish to answer • Questionnaire questions: What the user sees • One Internal may map to many questionnaire questions • Funnelling: From the general to the specific • Logical order: No forward references or dependencies • Break into topic sections CS2341

  8. Going to the Pub • Internal Question: “Making a plan to go to the pub” • Questionnaire Questions: • “Who do you go to the pub with?” • “Is it always the same people?” • “Which pubs do you visit?” • “Do you stay at one pub?” • “At what tiime do you usually go to the pub?” • “At what time do you usually return from the pub?” CS2341

  9. Question Types • Multiple-choice • limited response • free response • “With whom do you go to the pub?” • By yourself • With Friends • Work colleagues • Family • Other CS2341

  10. Questionnaire Tips • Tick boxes and multi-choice are well answered • Free response questions rarely answered • Time is precious – 30 minutes maximum • Facts easier to gather than behaviour • Time perception and memory are faulty • Readability is important • Make instructions clear – tick, cross, underline, choose one, many, at least one, etc. CS2341

  11. Question Wording • Avoid two questions in one: “Do you buy food and drink at the bar: y/n” • Avoid the word “not”: “Does the article not have an adequate abstract and introduction? Y/N” • “Why” questions are difficult to answer; offer concrete examples: “Tick any of the following reasons you may use to visit the pub:” • Use statements: “I go to the pub to meet friends” “Strong agree neither agree or disagree disagree” • No leading questions: “Do you want Soviet style women’s equality laws?” CS2341

  12. Limitations of Questionnaires • Difficult to interpret • Cannot follow digressions • Ensuring correct respondant interpretation • Quantitative, numeric responses means narrow questions • Qualitative, free responses give more information, but are difficult to analyse CS2341

  13. Uses of Questionnaires • Can quickly cover a large number of users • Useful for gathering basic information • Need to follow up with single user interviews • Can sketch out basic models CS2341

  14. The UML Process • Participatory design: the users are involved • Iterative – Segments are re-visited • User knowledge captured in a series of models and transformed to give an application design • Models shown to users for testing and modification CS2341

  15. Users and Activities • Users take part in Activities: Going for a drink • Activities involve objects: People, pub, chairs, table, beer, coca-cola • An object’s behaviour is invoked to take part in an activity: if (person.hasMoney()) then person.buyDrink(); CS2341

  16. UML Modelling Diagrams • Activity diagrams • Class diagrams • Use cases • Sequence diagrams • Employment diagrams • These and others all capture (model) some aspect of task and/or system CS2341

  17. The plan • Initial interview to gain overview • Should know main actors: Customers, bar staff, Landlord/lady, brewery rep, … • Organise in depth interviews with different actors • Find what activities they perform and how they are performed • Will take many sessions over extended time – client must commit CS2341

  18. The Bartender • “As a bartender, I do many jobs; the main one being serving customers. This can be any number of any type of drink. I also, check stock, collect glasses, wash glasses and eject drunkards.” CS2341

  19. The Personnel • The user • Note takers • Modellers • Facilitator • Remember ethics! • Plenty of pencils and paper – come with diagrams prepared from initial interviews: adapt as you go CS2341

  20. Using Interviews • Create Models and show to usersThis is participatory design • Responses will promt more interview questions • Iterative design and model refinement • “You mentioned dealing with a large number of drinks” • “yes, if they’re all the same its easy, but if they’re different, I KEEP FORGETTING…” CS2341

  21. Structured Interviews • Same general rules as questionnaires • Performed face to face • Digressions allowed, but controlled • A set of questions based on initial interview • Use user’s terminology • Tailor questions to types of user CS2341

  22. Bar Staff Interview • Describe, in general terms, your job • How many bar staff are there? • Do you work together or separately? • Do you share responsibilities? • Which other employees do you interact with? • How often do you colect glasses? How do you decide when to do this? • How many customers can you serve? • When do you refuse to serve? CS2341

  23. General Tips • Use a plan • You are not testing the users: they are helping you • One hour: repeat rather than tire • The users are helping • Do not interrogate users • Allow interesting diversions, but guide to the plan • Model as you go: Concrete is good CS2341

  24. Summary • Gathering user requirements is important • It is the input phase to your engineering task • There are many kinds of user, ncluding other systems • Plan your interaction and do it iteratively • Talking to users is difficult CS2341

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