1

Requirements: Elicitation

Mark E. Sampson

EMIS 8340

Systems Engineering Tool—applying tools to engineering systems

2

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]

3

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]www.wengerna.com

4

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]

5

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]

6

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)

7

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.)

8

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• What job are you ‘hiring’ my product to do?

[Linkedin: https://www.youtube.com/watch?v=5DwYcNr0Nuw ]

9

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

10

Requirements Elicitation Techniques…Delphi

• Get a bunch of experts together and work towards convergence

1. Ask questions2. Summarize/combine anonymous answers 3. Ask questions again until they converge

• How?• Paper Q&A • Web-based—e-Delphi• Survey tools—Grapevine,

SurveyMonkey, Zoomerang,…

“If panelists are misinformed about a topic, the use of Delphi may only add confidence to their ignorance”

--Wikipedia

www.techcast.org

11

Requirements Elicitation Techniques…MindMapping

• Draw out relationships with you stakeholders

1. Put the topic at the center 2. Draw relationships around it3. Keep going

• How?• Paper• Diagramming tools… Visio,

Freemind, Mindjet, Mindview,… • …

Lengthy list of Mindmapping tools on Wikipedia at: http://en.wikipedia.org/wiki/List_of_mind_mapping_software

12

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, surveymonkey, web-online-surveys,…• How to write questions to get to the information you need? http://www.statpac.com/surveys/

13

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)

14

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/demonstrationInformation Handling Services

15

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

16

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, Matlab, PVWave,…

Data Analysis Introduction &Demonstration

17

Search Engine Relationship Mining

Requirements from related items… …using various web-basedSearch engines to seekout related items.

Beware the Relevance Paradox

[SE Handbook 4.1; Pariser 2011 ]

People see information they perceive as relevant to them. There may be information that is not perceived as relevant because the seeker does not already have it and its relevance only becomes apparent after its been acquired [the paradox] …search engines return/filter out information based on prior search history. Meaning search engines return information from sources you agree with.

--Filter Bubble 2011

Bell’s telephone patent deemed useless for transmitting messages by patent evaluation committee -Evanson 2001

18

Finding Unintended Requirements

Requirements that come from unintended sourcesLaw of Unintended Consequences……messing around with a complex system makes it worse

Bad UiC’s… •Windmills and dead birds•Low-flush toilets backed up sewer systems •Rabbits introduced to Australia for hunting•Rat bounty Rat ranches •Corn subsidies for fuel Food prices increase•Fannie Mae underwrite low/moderate income mortgages•Energy-saving light bulbs Hazardous waste

Some UiC’s are good… •Yellow Sticky Notes•Teflon•Aspirin reduces heart attacks

[Bahill 2011]

19

The Allegory of the Humidifier

…foreseeing unintended consequences

[Sampson 1997]

20

Requirements Elicitation Techniques…other

• Role playing• Storyboarding• Prototyping• JAD (Joint Application Development)• Gaming• Web-crawlers & spiders…• Lunch table conversations…