Req Elicitation, Documenting Reqs, NatLang Reqs Lecture 3, DAT230, - - PowerPoint PPT Presentation

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Req Elicitation, Documenting Reqs, NatLang Reqs Lecture 3, DAT230, - - PowerPoint PPT Presentation

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Req Elicitation, Documenting Reqs, NatLang Reqs Lecture 3, DAT230, Requirements Engineering Robert Feldt, 2012-09-11 tisdag 11 september 12 Recap SWEBOK gives overview of SE field Good for newcomers and if you want to refresh At

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Req Elicitation, Documenting Reqs, NatLang Reqs

Lecture 3, DAT230, Requirements Engineering Robert Feldt, 2012-09-11

tisdag 11 september 12

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  • SWEBOK gives overview of SE field
  • Good for newcomers and if you want to refresh
  • At master level: Good idea to directly to original

sources; less need for “textbook” interpretations

  • Basic RE terminology in SWEBOK KA number 1
  • Stakeholder Identification
  • Stakeholder analysis: influence & affected, expectations

& interests

Recap

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What is Req Elicitation?

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“The art of determining the needs of stakeholders”

What is Req Elicitation?

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“The art of determining the needs of stakeholders” “The process of discovering the requirements for a system by communication with stakeholders and through the observation of them in their domain”

What is Req Elicitation?

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General rules for elicitation

  • Genuinely care about your stakeholders’ problems
  • Focus on stakeholder not on you “looking good”
  • Be human - admit weaknesses, become vulnerable,

show humor

  • Listen - eye contact, don’t glaze over
  • Expect changes
  • Maintain a glossary - many req problems from simple

misunderstandings/miscommunication

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Information to elicit

  • Domain description (operating environment)
  • Business goals ... Technical goals
  • System boundary (“fit into operational environment?”)
  • Constraints
  • Vocabulary
  • Reqs
  • Title, description
  • Rationale, Source, Importance, Benefit, etc...

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Different types of elicited reqs

  • Discovered: Stakeholder knows req - ReqEng notes it
  • Created: ReqEng creates based on own knowledge or
  • nly little stakeholder info
  • Extracted: ReqEng uses method to find it
  • Captured: When verbalized or acknowledged by

stakeholder

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Differing abstraction levels

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Differing abstraction levels

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Requirements Abstract Model (RAM)

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Triangulation

Use multiple things so that they partly say (and thus supports) the same conclusions (or finds the same problems/conflicts) “things” = methods, info, people, processes, documents, ...

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Triangulation

Elicitation Methods People / Stakeholders Artifacts / Docs

Interviews Observation ...

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Triangulation

Elicitation Methods People / Stakeholders Artifacts / Docs

Interviews Observation ...

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Triangulation

Elicitation Methods People / Stakeholders Artifacts / Docs

Interviews Observation ...

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Elicitation methods

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Elicitation methods

Interviews Questionnaires Doc analysis

“Traditional”/ Survey

Archaeology

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Elicitation methods

Interviews Questionnaires Doc analysis

“Traditional”/ Survey Group-based

Brainstorming JAD/RAD Focus groups Req Workshops Archaeology

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Elicitation methods

Interviews Questionnaires Doc analysis

“Traditional”/ Survey Group-based

Brainstorming JAD/RAD Focus groups Req Workshops

“Cognitive”/ Introspective

Think-aloud / Protocol Analysis Laddering Card sorting Repertory grids Archaeology

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Elicitation methods

Interviews Questionnaires Doc analysis

“Traditional”/ Survey Group-based

Brainstorming JAD/RAD Focus groups Req Workshops

“Cognitive”/ Introspective

Think-aloud / Protocol Analysis Laddering Card sorting Repertory grids

Contextual/ Observation

Ethnography Observation Conversation analysis Archaeology Apprenticing

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Elicitation methods

Interviews Questionnaires Doc analysis

“Traditional”/ Survey Group-based

Brainstorming JAD/RAD Focus groups Req Workshops

“Cognitive”/ Introspective

Think-aloud / Protocol Analysis Laddering Card sorting Repertory grids

Contextual/ Observation

Ethnography Observation Conversation analysis

Prototyping

Working prototypes Mashups Drawings Diagramming Archaeology Apprenticing

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Elicitation methods

Interviews Questionnaires Doc analysis

“Traditional”/ Survey Group-based

Brainstorming JAD/RAD Focus groups Req Workshops

“Cognitive”/ Introspective

Think-aloud / Protocol Analysis Laddering Card sorting Repertory grids

Contextual/ Observation

Ethnography Observation Conversation analysis

Model- or Spec-driven

KAOS I* CREWS

Prototyping

Working prototypes Mashups Drawings Diagramming Use Cases Archaeology Apprenticing

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SLIDE 23

Elicitation methods

Interviews Questionnaires Doc analysis

“Traditional”/ Survey Group-based

Brainstorming JAD/RAD Focus groups Req Workshops

“Cognitive”/ Introspective

Think-aloud / Protocol Analysis Laddering Card sorting Repertory grids

Contextual/ Observation

Ethnography Observation Conversation analysis

Model- or Spec-driven

KAOS I* CREWS

Prototyping

Working prototypes Mashups Drawings Diagramming Use Cases

Explicit

Archaeology Apprenticing

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Elicitation methods

Interviews Questionnaires Doc analysis

“Traditional”/ Survey Group-based

Brainstorming JAD/RAD Focus groups Req Workshops

“Cognitive”/ Introspective

Think-aloud / Protocol Analysis Laddering Card sorting Repertory grids

Contextual/ Observation

Ethnography Observation Conversation analysis

Model- or Spec-driven

KAOS I* CREWS

Prototyping

Working prototypes Mashups Drawings Diagramming Use Cases

Explicit

Archaeology Apprenticing

Implicit

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Elicitation methods

Interviews Questionnaires Doc analysis

“Traditional”/ Survey Group-based

Brainstorming JAD/RAD Focus groups Req Workshops

“Cognitive”/ Introspective

Think-aloud / Protocol Analysis Laddering Card sorting Repertory grids

Contextual/ Observation

Ethnography Observation Conversation analysis

Model- or Spec-driven

KAOS I* CREWS

Prototyping

Working prototypes Mashups Drawings Diagramming Use Cases

Explicit

Archaeology Apprenticing

Implicit Reflective

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Elicitation methods

Interviews Questionnaires Doc analysis

“Traditional”/ Survey Group-based

Brainstorming JAD/RAD Focus groups Req Workshops

“Cognitive”/ Introspective

Think-aloud / Protocol Analysis Laddering Card sorting Repertory grids

Contextual/ Observation

Ethnography Observation Conversation analysis

Model- or Spec-driven

KAOS I* CREWS

Prototyping

Working prototypes Mashups Drawings Diagramming Use Cases

Explicit

Archaeology Apprenticing

Implicit Reflective Creativity

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Elicitation methods

Interviews Questionnaires Doc analysis

“Traditional”/ Survey Group-based

Brainstorming JAD/RAD Focus groups Req Workshops

“Cognitive”/ Introspective

Think-aloud / Protocol Analysis Laddering Card sorting Repertory grids

Contextual/ Observation

Ethnography Observation Conversation analysis

Model- or Spec-driven

KAOS I* CREWS

Prototyping

Working prototypes Mashups Drawings Diagramming Use Cases

Explicit

Archaeology Apprenticing

Implicit Reflective Creativity Consensus

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Elicitation methods

Interviews Questionnaires Doc analysis

“Traditional”/ Survey Group-based

Brainstorming JAD/RAD Focus groups Req Workshops

“Cognitive”/ Introspective

Think-aloud / Protocol Analysis Laddering Card sorting Repertory grids

Contextual/ Observation

Ethnography Observation Conversation analysis

Model- or Spec-driven

KAOS I* CREWS

Prototyping

Working prototypes Mashups Drawings Diagramming Use Cases

Explicit

Archaeology Apprenticing

Implicit Reflective Creativity Consensus Reactive

tisdag 11 september 12

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Elicitation methods

Interviews Questionnaires Doc analysis

“Traditional”/ Survey Group-based

Brainstorming JAD/RAD Focus groups Req Workshops

“Cognitive”/ Introspective

Think-aloud / Protocol Analysis Laddering Card sorting Repertory grids

Contextual/ Observation

Ethnography Observation Conversation analysis

Model- or Spec-driven

KAOS I* CREWS

Prototyping

Working prototypes Mashups Drawings Diagramming Use Cases

Explicit

Archaeology Apprenticing

Implicit Reflective Creativity Consensus Reactive Refining

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Hierarchy of (non-group) Elicitation methods

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Elicitation techniques - early

Technique Pro Con

Interviews Know the present & future ideas, Uncover conflicts/politics Goals & critical issues, Subjective Group interviews/ sessions Stimulate/complete each other, Many/ Diverse stakeholders Censorship & domination, Groupthink Observation Actual current behavior, processes Time consuming, misses exceptional/ usability problems

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Elicitation techniques - early

Technique Pro Con

Interviews Know the present & future ideas, Uncover conflicts/politics Goals & critical issues, Subjective Group interviews/ sessions Stimulate/complete each other, Many/ Diverse stakeholders Censorship & domination, Groupthink Observation Actual current behavior, processes Time consuming, misses exceptional/ usability problems

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Elicitation techniques - early

Technique Pro Con

Interviews Know the present & future ideas, Uncover conflicts/politics Goals & critical issues, Subjective Group interviews/ sessions Stimulate/complete each other, Many/ Diverse stakeholders Censorship & domination, Groupthink Observation Actual current behavior, processes Time consuming, misses exceptional/ usability problems

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Elicitation techniques - mid

Technique Pro Con

Task demo Clarify how work done Presence & Qs influence, Critical issues seldom captured Questionnaires Info from many (statistics, views,

  • pinions)

Hard to construct, Interpretation Brainstorming Many ideas (none rejected) Many ideas (prioritization needed), Involvement

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Elicitation techniques - late

Technique Pro Con

Use cases / Scenarios Concentration on specifics => accuracy Solution-oriented, Premature design

Modeling, Data-flow Diagrams, ... Communication, Organize info, Uncover missing/ inconsistencies Require tools, Time consuming, “Cults”

Prototyping Visualization, Stimulate ideas, Usability centered Solution-oriented, Premature design, “Already done?”

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Brainstorming

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Research on how to elicit?

[Davis2006]

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Elicitation Guidelines

[Dieste2009]

Study excluded group techniques!

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Elicitation Guidelines

Interviews MORE EFFECTIVE than Introspective techniques & Sorting

[Dieste2009]

Study excluded group techniques!

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Elicitation Guidelines

Interviews MORE EFFECTIVE than Introspective techniques & Sorting Interviews MORE COMPLETE than Introspective techniques & Sorting

[Dieste2009]

Study excluded group techniques!

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Elicitation Guidelines

Interviews MORE EFFECTIVE than Introspective techniques & Sorting Interviews MORE COMPLETE than Introspective techniques & Sorting Interviews LESS EFFICIENT than Sorting & Laddering

[Dieste2009]

Study excluded group techniques!

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Elicitation Guidelines

Interviews MORE EFFECTIVE than Introspective techniques & Sorting Interviews MORE COMPLETE than Introspective techniques & Sorting Interviews LESS EFFICIENT than Sorting & Laddering Interviews has SAME EFFICIENCY as Introspective techniques

[Dieste2009]

Study excluded group techniques!

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Elicitation Guidelines

Interviews MORE EFFECTIVE than Introspective techniques & Sorting Interviews MORE COMPLETE than Introspective techniques & Sorting Interviews LESS EFFICIENT than Sorting & Laddering Interviews has SAME EFFICIENCY as Introspective techniques Introspective techniques WORSE than all others

[Dieste2009]

Study excluded group techniques!

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Elicitation Guidelines

Interviews MORE EFFECTIVE than Introspective techniques & Sorting Interviews MORE COMPLETE than Introspective techniques & Sorting Interviews LESS EFFICIENT than Sorting & Laddering Interviews has SAME EFFICIENCY as Introspective techniques Introspective techniques WORSE than all others Laddering PREFERABLE to Sorting

[Dieste2009]

Study excluded group techniques!

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Strategies for elicitation

Strategy Description Scenario Building Asking a user to imagine or construct a scenario in his domain, and respond as he would in that situation Conditionalizing Use “if-then” to limit or clarify applicability of an assertion Elaborating with examples Asking a user to illustrate a point by providing examples Hedging Asking a user to design contingency plans or fallback positions

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Strategies for elicitation

Strategy Description Scenario Building Asking a user to imagine or construct a scenario in his domain, and respond as he would in that situation Conditionalizing Use “if-then” to limit or clarify applicability of an assertion Elaborating with examples Asking a user to illustrate a point by providing examples Hedging Asking a user to design contingency plans or fallback positions

“Describe the most unusual customer you ever had. How did you respond in that situation?”

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Strategies for elicitation

Strategy Description Scenario Building Asking a user to imagine or construct a scenario in his domain, and respond as he would in that situation Conditionalizing Use “if-then” to limit or clarify applicability of an assertion Elaborating with examples Asking a user to illustrate a point by providing examples Hedging Asking a user to design contingency plans or fallback positions

“If the project is finished as planned, then what does that mean for the customer?”

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Strategies for elicitation

Strategy Description Scenario Building Asking a user to imagine or construct a scenario in his domain, and respond as he would in that situation Conditionalizing Use “if-then” to limit or clarify applicability of an assertion Elaborating with examples Asking a user to illustrate a point by providing examples Hedging Asking a user to design contingency plans or fallback positions

“Can you provide some examples of what you mean?”

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Strategies for elicitation

Strategy Description Scenario Building Asking a user to imagine or construct a scenario in his domain, and respond as he would in that situation Conditionalizing Use “if-then” to limit or clarify applicability of an assertion Elaborating with examples Asking a user to illustrate a point by providing examples Hedging Asking a user to design contingency plans or fallback positions

“What would you do if this action would not give the desired result?”

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Strategies for elicitation

Strategy Description Scenario Building Asking a user to imagine or construct a scenario in his domain, and respond as he would in that situation Conditionalizing Use “if-then” to limit or clarify applicability of an assertion Elaborating with examples Asking a user to illustrate a point by providing examples Hedging Asking a user to design contingency plans or fallback positions

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Strategies for elicitation

Strategy Description Generating Counterargument Asking a stakeholder to argue against the conclusion she first reached Generating Arguments Asking for more or different arguments favoring a position Feedback Asking for or giving feedback, either verbally

  • r in writing / on notes

Summarization Asking for or giving a summary

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Strategies for elicitation

Strategy Description Generating Counterargument Asking a stakeholder to argue against the conclusion she first reached Generating Arguments Asking for more or different arguments favoring a position Feedback Asking for or giving feedback, either verbally

  • r in writing / on notes

Summarization Asking for or giving a summary

“Why might the system not work as well as you say it will?”

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SLIDE 54

Strategies for elicitation

Strategy Description Generating Counterargument Asking a stakeholder to argue against the conclusion she first reached Generating Arguments Asking for more or different arguments favoring a position Feedback Asking for or giving feedback, either verbally

  • r in writing / on notes

Summarization Asking for or giving a summary

“Can you think of an analogy that would help clarify what you are saying?”

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SLIDE 55

Strategies for elicitation

Strategy Description Generating Counterargument Asking a stakeholder to argue against the conclusion she first reached Generating Arguments Asking for more or different arguments favoring a position Feedback Asking for or giving feedback, either verbally

  • r in writing / on notes

Summarization Asking for or giving a summary

“Let me recap what I have noted down from our conversation and you can see if you agree?”

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SLIDE 56

Strategies for elicitation

Strategy Description Generating Counterargument Asking a stakeholder to argue against the conclusion she first reached Generating Arguments Asking for more or different arguments favoring a position Feedback Asking for or giving feedback, either verbally

  • r in writing / on notes

Summarization Asking for or giving a summary

“Can you summarize what you have said so far?”

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SLIDE 57

Strategies for elicitation

Strategy Description Generating Counterargument Asking a stakeholder to argue against the conclusion she first reached Generating Arguments Asking for more or different arguments favoring a position Feedback Asking for or giving feedback, either verbally

  • r in writing / on notes

Summarization Asking for or giving a summary

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Task Characteristics Prompting

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Semantic Prompting

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Modernist vs Post-Modernist Perspective

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Modernist vs Post-Modernist Perspective

[Easterbrook2004]

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Modernist vs Post-Modernist Perspective

“Rationality is the highest form of mental functioning”

[Easterbrook2004]

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Modernist vs Post-Modernist Perspective

“Rationality is the highest form of mental functioning” “There is a universal truth and science uncovers it”

[Easterbrook2004]

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Modernist vs Post-Modernist Perspective

“Rationality is the highest form of mental functioning” “There is a universal truth and science uncovers it” “Rationality always leads to progress and perfection”

[Easterbrook2004]

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Modernist vs Post-Modernist Perspective

“Rationality is the highest form of mental functioning” “There is a universal truth and science uncovers it” “Rationality always leads to progress and perfection”

A Modernist Perspective

[Easterbrook2004]

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Modernist vs Post-Modernist Perspective

“Rationality is the highest form of mental functioning” “There is a universal truth and science uncovers it” “Rationality always leads to progress and perfection”

A Modernist Perspective

“Identify and Question the Grand Narrative”

[Easterbrook2004]

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Modernist vs Post-Modernist Perspective

“Rationality is the highest form of mental functioning” “There is a universal truth and science uncovers it” “Rationality always leads to progress and perfection”

A Modernist Perspective

“Identify and Question the Grand Narrative” “Find Mini-Narrative and DO NOT claim universality, truth or stability”

[Easterbrook2004]

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SLIDE 68

Modernist vs Post-Modernist Perspective

“Rationality is the highest form of mental functioning” “There is a universal truth and science uncovers it” “Rationality always leads to progress and perfection”

A Modernist Perspective

“Identify and Question the Grand Narrative” “Find Mini-Narrative and DO NOT claim universality, truth or stability”

A Post-Modernist Perspective

[Easterbrook2004]

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Modernist vs Post-Modernist ReqEng

“All observation is value-laden”

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Modernist vs Post-Modernist ReqEng

[Easterbrook2004]

“All observation is value-laden”

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Modernist vs Post-Modernist ReqEng

A Modernist Perspective

[Easterbrook2004]

“All observation is value-laden”

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SLIDE 72

Modernist vs Post-Modernist ReqEng

“Build consistent model & validate it is correct”

A Modernist Perspective

[Easterbrook2004]

“All observation is value-laden”

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SLIDE 73

Modernist vs Post-Modernist ReqEng

“Build consistent model & validate it is correct” Tools that test completeness and consistency

A Modernist Perspective

[Easterbrook2004]

“All observation is value-laden”

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SLIDE 74

Modernist vs Post-Modernist ReqEng

“Build consistent model & validate it is correct” Tools that test completeness and consistency

A Modernist Perspective

[Easterbrook2004]

Reviews to show model is valid ... “All observation is value-laden”

tisdag 11 september 12

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SLIDE 75

Modernist vs Post-Modernist ReqEng

“Build consistent model & validate it is correct” Tools that test completeness and consistency

A Modernist Perspective A Post-Modernist Perspective

[Easterbrook2004]

Reviews to show model is valid ... “All observation is value-laden”

tisdag 11 september 12

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SLIDE 76

Modernist vs Post-Modernist ReqEng

“Build consistent model & validate it is correct” Tools that test completeness and consistency

A Modernist Perspective

“No priviliged viewpoint”

A Post-Modernist Perspective

[Easterbrook2004]

Reviews to show model is valid ... “All observation is value-laden”

tisdag 11 september 12

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SLIDE 77

Modernist vs Post-Modernist ReqEng

“Build consistent model & validate it is correct” Tools that test completeness and consistency

A Modernist Perspective

“No priviliged viewpoint” Use stakeholder involvement so they “own” the models

A Post-Modernist Perspective

[Easterbrook2004]

Reviews to show model is valid ... “All observation is value-laden”

tisdag 11 september 12

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SLIDE 78

Modernist vs Post-Modernist ReqEng

“Build consistent model & validate it is correct” Tools that test completeness and consistency

A Modernist Perspective

“No priviliged viewpoint” Use stakeholder involvement so they “own” the models

A Post-Modernist Perspective

[Easterbrook2004]

Reviews to show model is valid ... “All observation is value-laden” Use ethnographic techniques to understand viewpoints

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SLIDE 79

Documenting requirements

  • Many both Internal and External needs:
  • Communication between roles/parties
  • Handle complexity of large systems & many requirements
  • Document decisions
  • Communication over time - a memory of decisions
  • Help ensure good requirements are elicited - avoid risks
  • Legal or contract disputes
  • Stability over time (Accessibility) - if people quit or move

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SRS Structures

Quite common in industry to have at least two levels of SRSes:

Refined

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SLIDE 81

SRS Structures

Quite common in industry to have at least two levels of SRSes:

Refined

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SLIDE 82

SRS Structures

Quite common in industry to have at least two levels of SRSes:

Refined

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SLIDE 83

IEEE standard 830-1998

http://www.cse.chalmers.se/~feldt/courses/reqeng/ examples/srs_example_2010_group2.pdf

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SLIDE 84

Natural Language Requirements

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Natural Language Requirements

Pro Con

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Natural Language Requirements

Pro Con Easiest to understand, requires “no” training Interpretation is often ambiguous

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SLIDE 87

Natural Language Requirements

Pro Con Easiest to understand, requires “no” training Interpretation is often ambiguous Can be used directly with customers Harder to separate different concerns

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SLIDE 88

Natural Language Requirements

Pro Con Easiest to understand, requires “no” training Interpretation is often ambiguous Can be used directly with customers Harder to separate different concerns Flexible & adaptable to the context No built-in support for completeness & Q criteria

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SLIDE 89

Natural Language Requirements

Pro Con Easiest to understand, requires “no” training Interpretation is often ambiguous Can be used directly with customers Harder to separate different concerns Flexible & adaptable to the context No built-in support for completeness & Q criteria Most common => most people used to it Harder to use in later development stages

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SLIDE 90

NatLang Ambiguities

  • 1. Nominalization:

Turns complex processes into single events Example: “In case of a system crash, a restart of the system shall be performed”

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SLIDE 91

NatLang Ambiguities

  • 2. Nouns without reference:

Vague nouns that are insuffiently specified. Example: “The output should be presented to the user in a graph”

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SLIDE 92

NatLang Ambiguities

  • 3. Universal quantifiers:

Applying too general statements to too many objects of some set. Missing quantities and frequencies. Example: “The system shall show all data sets in every graph view”

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SLIDE 93

NatLang Ambiguities

  • 4. Incompletely specified conditions:

Reqs often only hold under certain conditions, which are often not identified clearly enough. Example: “The restaurant system shall show all beverages to a guest over the age of 20.”

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NatLang Ambiguities

  • 5. Incompletely specified verbs:

Passive verb forms often allow for info to be missing. Try to use active voice! Example: “To log a user in, the login data is entered.” instead “The system must allow the user to enter user name and password using a keyboard.”

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SLIDE 95

References

[Dieste2009] Dieste, O. and Juristo, N., “Systematic Review and Aggregation

  • f Empirical Studies on Elicitation Techniques”, IEEE Transactions on

Software Engineering, vol. 37, num. 2, pp. 283-304, 2011. [Davis2006], Davis, A. and Dieste, O. and Hickey, A. and Juristo, N. and Moreno, A.M., “Effectiveness of requirements elicitation techniques: Empirical results derived from a systematic review”, 14th IEEE International Conference on Requirements Engineering, pp. 179-188, 2006. [Easterbrook2004] Steve Easterbrook, “Requirements engineering lecture slides” University of Toronto, 2004.

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