University of Toronto Department of Computer Science Lecture 3 Requirements Elicitation I Last Last Week Week Approaches Approachesto toRE RE Processes methods Processes methods techniques techniques Domains Domains Systems SystemsTheory Theory This This Week Week Elicitation Elicitation I I Traditional Traditional approaches approaches Interviews Interviews Questionnaires Questionnaires Scenarios Scenarios Goals Goals and and Use Cases Use Cases Next Next Week Week Elicitation Elicitation II II Cognitive Cognitiveapproaches approaches Contextual Contextualapproaches approaches Ethnography Ethnography 2000 2003 Steve Easterbrook 2 University of Toronto Department of Computer Science Requirements Elicitation Starting point Some notion that there is a problem that needs solving e g dissatisfaction with the current state of affairs e g a new business opportunity e g a potential saving of cost time resource usage etc Collect enough information to identify the problem opportunity Which problem needs to be solved identify problem Boundaries Where is the problem understand the Context Problem Domain Whose problem is it identify Stakeholders Why does it need solving identify the stakeholders Goals How might a software system help collect some Scenarios When does it need solving identify Development Constraints What might prevent us solving it identify Feasibility and Risk become an expert in the problem domain W6H W6H The The journalist s journalist s technique technique What What Where Where Who Who Why Why When When How How Which Which Learn how to find your way round a new problem area quickly Use your initial ignorance as an excuse to ask questions Recognise the domain expertise of the people you talk to 2000 2003 Steve Easterbrook 3 1 University of Toronto Department of Computer Science The four worlds Maintains information about Needs information about Subject World Uses System World Usage World builds contracts Development World 2000 2003 Steve Easterbrook 4 Source Adapted from Loucopoulos Karakostas 1995 p73 University of Toronto Department of Computer Science Finding out about the four worlds Subject World the subject matter of the information system e g customers accounts transactions for a bank information system Usage World the environment within which the planned system will operate e g people such as managers clerks customers also business processes such as handling a withdrawal a deposit of foreign currency System World what the system does within its operational environment what information it contains and what functions it performs e g system records all transactions in a database reports on transactions for a particular account gives account balance Development World the development process team schedule required qualities security performance etc e g system to be delivered in 12 months fully tested to MCDC standard etc 2000 2003 Steve Easterbrook 5 2 University of Toronto Department of Computer Science Stakeholders Stakeholder analysis Identify all the people who must be consulted during information acquisition Look for stakeholders associated with each of the four worlds Example stakeholders Users concerned with the features and functionality of the new system Designers want to build a perfect system or reuse existing code Systems analysts want to get the requirements right Training and user support staff want to make sure the new system is usable and manageable Business analysts want to make sure we are doing better than the competition Technical authors will prepare user manuals and other documentation for the new system The project manager wants to complete the project on time within budget with all objectives met the customer whoever it is that pays for the new system 2000 2003 Steve Easterbrook 6 University of Toronto Department of Computer Science Difficulties of Elicitation Thin spread of domain knowledge The knowledge might be distributed across many sources It is rarely available in an explicit form I e not written down There will be conflicts between knowledge from different sources People have conflicting goals People have different understandings of the problem Tacit knowledge The say do problem People find it hard to describe knowledge they regularly use Descriptions may be inaccurate rationalizations of expert behaviour Limited Observability The problem owners might be too busy solving it using the existing system Presence of an observer may change the problem E g the Probe Effect and the Hawthorne Effect Bias People may not be free to tell you what you need to know Political climate organisational factors matter People may not want to tell you what you need to know The outcome will affect them so they may try to influence you hidden agendas 2000 2003 Steve Easterbrook 7 3 University of Toronto Department of Computer Science Example The problem area Loan approval department in a large bank The analyst is trying to elicit the rules and procedures for approving a loan Why this might be difficult Implicit knowledge There is no document in which the rules for approving loans are written down Conflicting information Different members of the department have different ideas about what the rules are Say do problem The loan approval process described to you by the loan approval officers is quite different from your observations of what they actually do Probe effect The loan approval process used by the officers while you are observing is different from the one they normally use Bias The loan approval officers fear that your job is to computerize their jobs out of existence so they are deliberately emphasizing the need for case by case discretion to convince you it has to be done by a human 2000 2003 Steve Easterbrook University of Toronto What 8 Expert Bias is bias Bias only exists in relation to some reference point can there ever be no bias reflects reality or truth We cannot perceive reality directly It is interpreted through a filter of mental models mediated by our senses and neural pathways All decision making is based partly on personal value systems Types of bias Motivational bias the expert makes accommodations to please the interviewer or some other audience Cognitive bias the expert does not follow objective rules or standards 2000 2003 Steve Easterbrook Department of Computer Science Sources Sources of of Bias Bias Social Socialpressure pressure response to verbal and non verbal cues from an interviewer response to verbal and non verbal cues from an