Writing eliciting good rqmts 082311

© 2011 IBM Corporation

Michelle Specht

Writing and Eliciting Good Requirements

Michelle Specht

7/23/2011


Software and Systems Engineering | Rational

2

Agenda

The Importance of Good Requirements

The Challenges of Developing Good Requirements

Writing Requirements

Requirements Elicitation

Using Requirements Management tools


Michelle Specht

The Importance of Good Requirements



4

If you do not know where you are

going….you will wind up

somewhere else!!Yogi Berra

Most of us have learned this lesson and it is why we value requirements as a critical part of systems and software development

Why We Need Requirements



5

Requirements Definition and Management Business Realities Traditional methods yield excess rework, delays & poor quality

20

200

Rel

ati

ve

Co

st

to R

ep

air

AcceptanceQA TestCodingDesignAnalysis

0

Maintenance

10

5

50

1-2

Lost Opportunity

Late to market by 6 months or more will cost organizations 33% of the 5-year ROI

41% of projects fail to deliver expected business ROI

49% of projects overrun original estimates

-Standish Group

Cost

70-80% of development costs are spent identifying and correcting defects

More than 40% of development budget will be consumed by poor requirements



6

The purpose of requirements and requirement management

Requirements and Requirement management need to do two things:

1) Validate - Make sure you are building the right product:

Are we doing the right thing?

2) Verify - Make sure you built the product right:

Are we doing the thing right?



7

What can happen when Requirements are not done right:


Michelle Specht

The Challenges of Developing Good Requirements



9

Poor Requirements Practices Pose Significant Challenges Across Teams

We struggle with budgets and can’t consistently meet

customer needs

Executive

Analyst

It’s hard to accurately capture requirements & make sure

they are implemented & tested

We can’t keep up with requirement changes and

know what is most important to develop and test

Development and Test teams

Quality Manager

Improve Quality

Efficiency

+Innovation

Reduce Cost

Accelerate Delivery

Time

We are continuously pushed to increase quality with less

resources!



10

Safety

Regulatory compliance

Development timescales

Project scale

Project life

…

Cost

Quality Time

Different industries have different needs…



11

Engineers like to solve problems

Measure twice, cut once Look before you leap

Thinking before you act saves time, money, effort and improves quality. It’s plain common sense, yet, when it comes to requirements management, this common sense seems not to be there. Many projects start before thought has been put into the project’s purpose, its desired results, and how its success will ultimately be measured.



12

Working with Requirements is a lifecycle activity

You need to enable requirements to evolve during the lifecycle

– Increase the likelihood of delivering value early

– Minimizes risk

– Minimizes re-work

– Reduces confusion

– Improves quality



13

Requirements are always changing

Changes in environment (e.g. new threats) lead to changes in stakeholder needs

Changes in technology (e.g. cheaper memory) lead to new stakeholder requirements and possible solutions that are cheaper, faster, etc.

Changes in stakeholders (e.g. new customer in charge) lead new views and new stakeholder requirements

Changes in budget ( e.g. funding cut) funding lost

And the longer your development timescale the greater the chance that requirements will change during your project



14

Requirements come from everywhere

Requirements

Obj

ectiv

eG

oalAim

Reg

ulat

ion

Criterion NeedFeat

ureFunction R

ule

Ris

k



15

People over design

Programs are getting so complex put solutions do not always need to be complicated. The simplest solution is usually the best. John Deere fuel tank sight gauge is a great example of this



16

There are many different types of requirements

Stakeholder Requirements

Architectural Requirements

Structural Requirements

Behavioral Requirements

SystemsFunctional Requirements

Non-functional Requirements

Performance Requirements

Design Requirements

Derived Requirements

Allocated Requirements

……….



17

Factors which complicate Requirements Management

Multiple requirement sets

Large number of requirements

Different levels of requirements

Version control

Change control

Product lines

Distributed teams

Different processes

Impact of changes

Systems of systems

Convergence of old and new technologies


Michelle Specht

Writing Requirements



19

Requirement Writing

The art of writing requirements takes great skill and, like writing code, the end result is usually cleaner and more consistent if there’s a single author.

Don’t expect to get the requirements 100% correct. You need to allow for human nature and use the same language as your client.

The following guideline gives 13 tips on how to write better requirements by following simple rules for word selection and sentence structure.

Most of these guidelines only apply to the requirement statements, not the complete specification.



20

Requirement Writing

1: Use the simplest words appropriate to state a complete requirement.

– An eloquently written requirement is probably not a good one.

– A requirement must be written so many different people can understand it.



21

Requirement Writing

2: Use requirement imperatives correctly.

– Use company/program defined list.

– If requirements are from a non-company source, make sure you know the meaning of these words. (Definitions should be included in Section 1 of the specification)

Common imperative definitions;

“Shall” Definition

“Shall” denotes a mandatory and contractual requirement. “Shall” requires metrics to quantify and requires a verification process.

“Will” Definition

“Will” denotes a mandatory and contractual requirement. It is similar to “shall” but does not require metrics or verification.

“Should” Definition

“Should” denote a design goal, an objective the system tries to meet.



22

Requirement Writing

Adequate

As Appropriate

Bad

Better

But not limited to

Correct

Easy

Effective

Ideal

Large

Maximize

Minimize

Most

Must

Necessary Normal Quick Rapid Readily Relevant Satisfactory Shall not Small Sufficient Suitable Timely Typical User friendly Was

3: Do not use weak phrases and subjective words.

Following are words and phases not to use when writing a requirement:



23

Requirement Writing

4: Use continuations carefully, they make traceability and verification difficult. Use when all items are to be verified by the same method at the same time.

Example:

– The system shall report software status to the host interface under the following conditions:

• At system initialization.

• When the status of an external interface has changed.

• When a report has been requested.

5: Use examples, tables, figures etc., they are a great source of information and clarification. – Make sure examples and notes are clearly marked as such (not part of requirement).

– For tables; specify if all, some or none of the cells are requirements.

– Clearly indicate if a figure or part of the figure, is part of the requirement, or is information.



24

Requirement Writing

6: Be consistent with names; always call the same entity by the same name. – Example: If in some requirements the subject is called “the System,” and in others “ the URQ-65”, the

names are not consistent.

– Always use the correct name for the level of specification. You can not verify a sub capability at a systems level.

7: If you use a TBD or TBR, have a plan. You must state who is responsible for the information, and when the it will be completed.



25

Requirement Writing

8: Make sure a requirement contains all the qualities of a good requirements

– Concise: Minimal, easily understood, a complete expression of a single thought, non-ambiguous; only one possible interpretation.

– Correct: An absence of errors of fact.

– Consistent: No conflicts between individual requirements, parts of a single requirement complement each other. Connectivity exists between the requirements; consistent words and terms

– Traceable: Know source of requirement and be able to allocate it, Uniquely identified for life. Never re-used identification on Project.

– Verifiable: Method (Test, Inspection, Demonstration, Analysis, Certification) Understand how requirement can be verified, and determine criteria for acceptance.

– Necessary: Can the system be complete without this requirement?

– Attainable: Is this requirement technically feasible within given time and cost?

– Modular: Will a change to this requirement have a big impact on the system? Can this requirement be easily used and monitored by other programs if needed?

– Restrictive – The requirement should written in such a way as to not limit implementation. Make sure the requirement states what needs to be done not how.



26

Requirement Writing

9: Conjunctions. There should be only one requirement per statement.– A requirement should not contain “and” or “or”.

– Requirement which contain “and”, “or” or “and/or” probably contain more than one requirements. These hard to trace and completely verify.

10: Make sure that if a requirement references another document, that it does so correctly. – State if reference is information or part of the requirement.

– Make sure references are listed in applicable document section and state what part of reference applies



27

Requirement Writing

11: Make sure Acronyms are used correctly.– Place the acronym in the acronym list in the specification.

– Spell out the complete phrase followed by the acronym in parenthesis the first time used.

– The next time just use the acronym.

– Example: first use: “The SATCOM Antenna Interface Unit (SAIU) shall…”, second use “The SAIU shall…”

12: Overspecification leads to unfunded requirements, and can add duplicate requirements. – The length of a requirement should not be excessive.



28

Requirement Writing

13: Use the requirement templateThere are four major parts to a requirement:

– Entities –

• Subject of the requirements (noun)

• Object of action (noun)

– Actions – What the subject does, contains imperative (verb)

– Conditions – What must be in place in order for this action to take place

– Constraints– Qualifies the action, performance

The following is the structure of a basic requirement:

[Conditions] [Subject] [Action] [Object] [Constraint]

Example:

When signal x is received [Conditions] , the system [Subject] shall set [Action] the signal x received bit [Object] within 2 seconds [Constraint].


Michelle Specht

Requirements Elicitation



30

Requirement Elicitation

The development process starts with understanding the client’s “business requirements”.

For the success of any project, an agreed upon understanding of the desired capability is extremely critical.

Requirements elicitation is the process of identifying the sources of requirements for a new project and obtaining those requirements from those sources.

The most important outcome is that the people who need to understand the requirements can do so.



31


There are many ways in which requirements can be gathered, there are several requirements elicitation techniques available to use

You should gather requirements using whichever method works for you. Whether you prefer a written document, screen diagrams, prototyping or use cases

Keep in mind that your choice of techniques will depend on your comfort level or familiarity, the complexity or nature of your project as well as the stakeholders you are talking to.

Each requirements elicitation technique has its advantages and disadvantages and that there is no one technique that works for every situation.

The following are some popular and recommended techniques for requirements elicitation:



32


1. Interviews: This technique uses a series of questions to extract information from the stakeholder, that focus on the client’s perspective, develops an understanding of the problem and finally evaluates the effectiveness of the meeting.

2. Document Review: All effective requirements elicitation involves some level of document analysis such as business plans, markets studies, contracts, requests for proposals, statements of work, existing guidelines, analyses of existing systems, and procedures. Improved requirements coverage results from identifying and consulting all likely sources of requirements.



33


3. Brainstorming: Brainstorming is a powerful technique because the most creative or effective ideas often result from combining seemingly unrelated ideas. Also, this technique encourages original thinking and the proposal of unusual ideas. Brainstorming involves both idea generation and idea reduction. The goal of the former is to identify as many ideas as possible, while the latter ranks the ideas into those considered most useful by the group.

4. Use Cases: A use case is a picture of actions that a system performs by depicting the actions. This should be accompanied by a textual description and should not be used in isolation from other requirements gathering techniques. Use cases and scenarios are known for facilitating team communication. They provide a context for the requirements by expressing the sequence of events and a common language for the end users and the technical team.



34


5. Requirements Workshops: This technique is considered very powerful for eliciting requirements because they can be designed to encourage consensus concerning the requirements of a particular capability. Other advantages that are achieved by this technique includes commitment of participants to the work products and project success, teamwork, resolution of political issues and reaching consensus on a host of topics.

6. Prototyping: This technique helps in building a quick and rough version of the desired system or parts of the system. This illustrates the capabilities of the system to users and designers. This technique serves as an excellent means of communication mechanism for all reviewers in understanding the interactions with the system. This sometimes gives an overly optimistic impression of completion possibilities since an impression is created that the developers are further along than is actually the case. Prototypes can be combined very effectively with other approaches such as JAD and models.



35


7. Storyboards: This technique is a set of drawings depicting a set of user activities that occur in an existing or envisioned system or capability. Storyboards may be thought of as forms of paper prototyping. In this technique, the Customers, Users or developers start by drawing pictures of the screens, dialogs, toolbars and other elements they believe the software should provide. These drawings are evolved by the group till the real requirements and details are worked out and agreed upon. This technique is in expensive and eliminates the risks and higher costs of prototyping.

8 Interfaces Analysis: One of the major causes of overrun is missing or incorrect interface. Identifying the external interfaces early clarifies product scope, aids risk assessment, reduces product development costs, and improves customer satisfaction. The steps of identifying, simplifying, controlling and monitoring interfaces help to reduce the risk of problems related to interfaces.



36


9. Glossary: to use the same language as your client. If the language is consistent, it greatly lowers the risk of misinterpretation of the requirements. Problems can develop if we didn’t use the same terms as the client. To avoid this problem is to include a glossary of terms and definitions in the requirements document.

10. Modeling: A model is a representation of reality or level of abstraction that is intended to facilitate understanding. They help eliminate ambiguities and inconsistencies and are correlated with the most successful projects.



37


11. Separate the problem and solution space: It is important to keep requirement elicitation implementation free. You should be working on understanding the problem, not solving it. Not keeping the requirements elicitation design free can create unnecessary restrictions and your product



38


12. Validating Requirements: One of the key activities to determine you have the right set of requirements is the requirement Validation: Before we accept requirements from Systems or a customer, we need to review the requirement set to see the quality of the requirements. This would let us know what is missing and what work needs to be done to the requirements. Can now develop a plan to address requirement needs.


Michelle Specht

Using Requirement Management Tools



40

Query attributes to find specific properties– “How many requirements are listed as high risk?”

Use traceability reports for checking dependencies– Before change is committed

Find “missing” links– “Which detailed requirements has no relation to a

high-level user requirement?” Coverage analysis

– “Which higher level requirement has no lower-level requirement?”

Impact analysis– “What lower level requirements are affected if a high

level requirement changes?” Keep traceability

– For each increment, if you develop incrementally with concurrent phases

– For each variant, if you manage variants and product lines

The benefits of good requirements engineering tools...



41

Rational Requirements Definition and Management SolutionEnabling business & technology experts to build business value

41

Requirements ManagementRational DOORS & Rational RequisitePro

Understand the impact of change as it occurs and ensure full traceability to

better manage project risk

Search, filter on attributes

Traceability between related

artifacts

Impact & Coverage analysis

Business Objectives

Business Processes

Storyboards

Requirements DefinitionRational Requirements Composer

Elicit, capture, elaborate, review and discuss requirements using a variety of techniques and notations

Rich text Documents

Achieve stakeholder consensus early and often in the development lifecycle to reduce rework and improve time to market

Improve collaboration among distributed teams to increase productivity and quality

Insure alignment of business and IT through linking and traceability of requirements artifacts to increase reuse and ensure effective software delivery

Use Cases

Prototypes

Visual Validation

Sketches



42

More information

Requirement management and definition webpage:

Rational RM Solutions

http://www-01.ibm.com/software/rational/offerings/irm/



43

Rational Publishing Engine: Document automation across the development lifecycle

Quickly and accurately create the right document for your development domain at the required time

Access data from a wide range of Rational tools, including:

DOORS ClearCase/ClearQuest Focal Point System Architect Rational Quality Manager RequisitePro Rhapsody Rational Requirements Composer Team Concert Test Manager

Access data from third party tools via XML and REST interfaces

Out-of-the-box document templates provided for quick ROI



44

RPE – Can create a document from multiple sources.This document extracts data from DOORS, ClearQuest and Rhapsody



45

Smarter healthcare

Smarter electronic devices

Smarter defense systems

Smarter energy

Smarter hybrid

technologies

Smarter automobiles

Smarter Requirements Build Smarter Products

45

Innovation for a smarter planet



46



47

Systems and Software Engineering Symposiums



48

Upcoming symposiums

Landing page for all Symposiums: http://www.ibm.com/events/systemsengineeringsymposium

http://www.ibm.com/events/systemsengineeringsymposium



49

Upcoming symposium

Adobe Acrobat Document

DC Flyer



50

© Copyright IBM Corporation 2008. All rights reserved. The information contained in these materials is provided for informational purposes only, and is provided AS IS without warranty of any kind, express or implied. IBM shall not be responsible for any damages arising out of the use of, or otherwise related to, these materials. Nothing contained in these materials is intended to, nor shall have the effect of, creating any warranties or representations from IBM or its suppliers or licensors, or altering the terms and conditions of the applicable license agreement governing the use of IBM software. References in these materials to IBM products, programs, or services do not imply that they will be available in all countries in which IBM operates. Product release dates and/or capabilities referenced in these materials may change at any time at IBM’s sole discretion based on market opportunities or other factors, and are not intended to be a commitment to future product or feature availability in any way. IBM, the IBM logo, Rational, the Rational logo, and other IBM products and services are trademarks of the International Business Machines Corporation, in the United States, other countries or both. Other company, product, or service names may be trademarks or service marks of others.

Learn more at: IBM Rational software IBM Rational Software Delivery Platform Process and portfolio management Change and release management Quality management Architecture management

Rational trial downloads Leading Innovation Web site developerWorks Rational IBM Rational TV IBM Business Partners IBM Rational Case Studies

http://www.ibm.com/software/rational

http://www-306.ibm.com/software/info/developer/index.jsp

http://www-306.ibm.com/software/rational/offerings/lifecycle.html

http://www-306.ibm.com/software/rational/offerings/scm.html

http://www-306.ibm.com/software/rational/offerings/testing.html

http://www-306.ibm.com/software/rational/offerings/design.html

http://www.ibm.com/developerworks/rational/downloads/?S_TACT=105AGX23&S_CMP=RCD

http://www-306.ibm.com/software/rational/leadership/leaders/

http://www.ibm.com/developerworks/rational

http://www-306.ibm.com/software/info/television/index.jsp?cat=rational&media=video&item=en_us/rational/xml/M259765N40519Z80.xml

http://www-306.ibm.com/software/rational/partners/

http://www-01.ibm.com/software/success/cssdb.nsf/topstoriesFM?OpenForm&Site=rational

Writing eliciting good rqmts 082311

Technology

Transcript of Writing eliciting good rqmts 082311