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Requirements: Elicitation

Mark E. Sampson

UPDATED 9/02/04

EMIS 8390

Systems Engineering Tool—applying tools to engineering systems

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Requirements Elicitation

• Standish Group claims “lack of user input” is one of the main contributors to runaway projects.• Some quotes:

“15% of projects fail outright, 51% are challenged” Standish

“53% of projects will cost 189% of estimates” Standish

“only 67% of originally defined features show up in the finished product, of those 45% are NEVER used” Standish

“half of resources spent on product development are spent on products that fail” 2003 Harvard Business School Cyberposium

“90% of electronics components function as designed, 50% of them fail when integrated with their systems” IEEE Design Magazine

…the process of discovering the requirements for a system by communication with customers, users, and other stakeholders. [Sommerville, 1997]

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Requirements Elicitation Problems…”Yes, but”

• “Yes, but…”…that’s so cool, but it would be nice if it…

• Caused by human nature• Anticipate some “buts…”• Do them early in the process with prototypes• Tend to be at the interfaces/touch points

[Leffingwell, 2000]

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Requirements Elicitation Problems…”Gold Miner”

• “When are you rich enough” …let’s do another pass by……there’s a few more avenues we haven’t checked…

• Systems Engineering nature• Scope statement boundaries the problem and establishes your objectives (how you know when you’ve arrived). When the extracted requirements adequately address your objectives…your there.

[Leffingwell, 2000]

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Requirements Elicitation Problems…”bring me a rock”

• Users don’t know what they want • Prototyping• Stick with it until you get some definition• Watch them in action (beware the Hawthorne effect)

[Leffingwell, 2000]

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Requirements Elicitation Techniques…Reuse

• Find if it’s already been done and reuse it.• Saves money & time• Reduces risk

• How?

• TRIZ uses inventive patterns (see class 1)• Analogs…Nature (already worked out the kinks)

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Analog: Anatomy of a project...

Epidermal System(facilities, security)

Skeletal System(project support groups)

Digestive System(Personnel, financeprovides energy/resourcesfor project)

Nervous System(SE & SE Tools--connectsmanagement to project)

Brain(Project Management)

Respiratory System(Marketing bringing innew ideas)

Circulatory System(Information Systems, LAN’s, PDM)

Muscular System(Does the work…engineering, etc.)

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Requirements Elicitation Techniques…Interviews

• Find a user/customer and ask them.• Proves there is a need.• Boundaries the market• Live communication, builds relationship with market

• How?

• Unbiased questions…”who is the user”? • Ask Why? Solutions Selling.

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Requirements Elicitation Techniques…Brainstorming

• Find a user/customer and brainstorm around a problem (see class 1).

• Idea generation and reduction• Combine ideas• Voting schemes

• How?

• Live, using stickee note • Web-based brainstorming• A variety of techniques supported by tools--Delphi, mindmaps,…both installed and web-based

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Requirements Elicitation Techniques…Surveys

• Find a potential user and get them to answer some survey questions.

• more efficient to cover a wide swath of potential users• Statistically measurable/confidence

• How?• Paper • Web-based Surveys—TcCommunity, grapevine, formsite, web-online-surveys,…• How to write questions to get to the information you need? http://www.statpac.com/surveys/

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Requirements Elicitation Techniques…Use Cases

• User interaction model• Identify who, what & how of product behavior• Describe the interaction between user and system—what the system does for the user• Describe functional behavior

• How?

• Modeling environments that support UML • Drawing/diagramming tools (Visio, PPT)

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Requirements Elicitation Techniques…Regulations/Standards

• Describe what the product must comply with… …another source of requirements

…constraints/drivers point out things you can do nothing about…

Where do you get themfrom?

Introduction/demonstrationWith George Bell/Steve HaasInformation Handling Services

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Requirements Elicitation Techniques…Scenario Generators

• Virtual environments describing aspects that impact our system

• Weather/environment • Economic/Financial (ALM, ESG,…)• Missions (TAC Brawler), Electronics (EWSG)

…produces an eventchain/time line that can drive out requirements (…must deal with 3 targets at the same time)

J-STARSw ATR

U-2

CAOC

UAV

DCGS

AEGIS

USMCTAOC

AIR DEFENSETOC

TADITADIL L

NETNET

TADITADIL L

NETNET

BCC

ARMY TacticalOperations Center

XX

XX

XXX

XX

TCT Kill Chain TCT Kill Chain Engaged by a Joint Battle ForceEngaged by a Joint Battle Force

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Requirements Elicitation Techniques…Data Mining

• Similar to reuse, except it relies on prior data to drive out requirements. The problem is finding the needle in the haystack……for example: Beer and Diaper Sales spike ~8:00pm

• start with existing data and look for anomalies/patterns

Tools…Probe, KD1, PVWave,…

Data Analysis Introduction &Demonstration with Hiedi Hager Visual Numerics

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Requirements Elicitation Techniques…other

• Role playing• Storyboarding• Prototyping• JAD (Joint Application Development)• Delphi• Gaming•…