Requirements

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+Requirements


+Real requirements

Client : You seem to be the kind of guy who know what you are doing?

Client : Educate me : What do you get when you rob a store ?

Thief: Answer : money

Client : How much give me a number ?

Thief : 500 bucks

Owner : That’s not possible

Client : OK let’s say a minimum hundred. If you get shot than it emergency will cost you a 1000 bucks .

Client : What are you going to buy with the money?

Thief : Beer and Sandwich

Client : How does 50 bucks of beer and sandwich sounds to you? I assume you are going to run. That’s all what you can carry?


+Definion of requirementsWhat is a Requirement?

A requirement is something wanted or needed

Formally documented and written statements

Capabilities needed to solve a problem

Conditions of a delivered system, services, product, or process

Constraints on the system, service, product, or process

Requirements are not :

Verbal, informal statements or conversations in the hallways

Solutions that state how to solve the problem or meet the objectives

Characteristics of other systems, services, products, or processes

Project budgets, plans, or implementation details


+What are requirements ?

Conditions or capabilities needed by a user/stakeholder

to solve problem or achieve an objective

Scope : the sum of the products, services and results to be provided as a project

Project Scope : the work that must be performed to deliver a product, service or result with thespecified features and functions

Product Scope : the features and functions that characterize the product, service or result www.relaxedprojectmanager.com


+What should happen ?


+How to get close to the real requirements ?


+The importance of requirements

Stakeholders

Interests

Requirements

Product/Service


+Reasons for failure


+Is there something like « real » requirements

People don’t express what they really need, they express what they think they need

Esteem andBelonging needs

Safety needs

Self Realisation


+Why? Why? Why?

Problem: Your client is refusing to pay for the leaflets you printed for them.

Why? The delivery was late, so the leaflets couldn't be used.

Why? The job took longer than we anticipated.

Why? We ran out of printer ink.

Why? The ink was all used up on a big, last-minute order.

Why? We didn't have enough in stock, and we couldn't order it in quickly enough.

Counter-measure: We need to find a supplier who can deliver ink at very short notice.


+Pain


+Maslows pyramid of hierarchies


+Requirements come from business needs

You need to know the business model

On the internet : Advertising – Affiliates – Brokerage - Merchant – Subscription – Information Community


+ “Set as a clockwork” : McDonald’s

Position : The first and best know fast food companyProcess value: Easy food, clean, quick process for young, they get used to the food and will be also customers when they are adult.Processus clefs : garantie of fresh food. Structure : Three layers of management(Restaurant Manager, First Assistant Manager, Floor Manager, Crew)Pouvoir : Business model is centralised (Marketing, business model, etc.). Human ressources are decentralised. Culture : Quick serving, fresh products, consumerism, US culture …


+Where’s the pain?

The first and best known fast food company

Easy food, clean, quick process for young, they get used to the

food and will be also customers when they are adult.

garantie of fresh food.

Three layers of management(Restaurant Manager, First Assistant

Manager, Floor Manager, Crew)

Business model is centralised (Marketing, business model, etc.).

Human ressources are decentralised.

Quick serving, fresh products, consumerism, US culture …


+What does this means for requirements ?

Constraints === Requirements


+Organisational Culture

onnel


+Requirements

Business

Organisation

Individuals

Constraints === Requirements


+What happens by not adressing the requirements/constraints


+Failure : Segway

$100 million developing the product Price point too high for mass consumer base Classiefied road vehicle and required licencing


+Failure : Cosmopolitan Yogurt

58 international editions Client need is not yogurt


+Kano

Delighters (surprise curve)

PerformanceNeeds curve

BasicNeeds

(Must have curve)

Notimplemented

DegreeOf fullfillement

Dissatisfied

Customersatisfaction

Un conscious demandUnexpected/not declared

Expected/Not declared


+Methods and Tools to understand requirements


+What is Requirements Elicitation? Elicitation: gathering and understanding what

stakeholders and users need Done at both an organizational (business) and a more

detailed user level Elicitation is a human-based activity

Determine requirements sources Decide how to gather information

Involves research, reading, talking, and observing Business-level context and framework

How the end users do their jobsWhat would help them do their jobs better

Within the scope of our system, product, or process


+How to find requirements ?

1. Lighter in stock

2. Point of Sale

4. Household waste

3. User lights a cigarette

Stakeholder 1Stakeholder 2

Stakeholder 6Stakeholder 7 Stakeholder 8

Stakeholder 3

Stakeholder 4Stakeholder 5

Stakeholder 9



+How to gather requirements ?

SurveyMarket StudyInterview

WorkshopBrainstorm

Meeting

Prototypage



+Interview technique

Generally easy, because it can be done with minimal preparation.

Interviews of individuals and small groups require less planning and scheduling effort than large workshops.

Interviews of individuals and small groups require less stakeholder commitment than large workshops.

Interviews provide an opportunity to explore or clarify topics in more detail.

The questions used in the interview may reflect the interviewer’s preconceived ideas, which can influence the responses.

For projects with a large number of stakeholders the interviews technique can be time-consuming and inefficient.

Conflicts and inconsistencies between stakeholder information need to be resolved in additional interviews.

This technique does not allow different stakeholders to hear and elaborate upon the information being relayed.

Advantages Disadvantages


+Joint Application Development (JAD) Techniques

This technique allows for the simultaneous gathering and consolidating of large amounts of information.

This technique produces relatively large amounts of high-quality information in a short period of time.

Discrepancies are resolved immediately with the aid of the facilitator.

This technique provides a forum to explore multiple points of view regarding a topic.

Requires significant planning and scheduling effort.

Requires significant stakeholder commitment of time and effort.

Requires trained and experienced personnel for facilitation and recording.



+Survey method

A survey can reach a large number of stakeholders or other sources of information.

A survey is an excellent tool to gather a significant amount of focused data in a short period of time.

Survey method can provide good results when used to validate assumptions after the use of the interviewing technique.

A Survey method is a good tool to gather statistical preference data.

A survey requires little scheduling effort.

A survey requires little stakeholder commitment of time and effort.

The response level is often low, especially to large surveys.

Responses are usually limited to the realm of the questions asked, which reflect the analyst’s preconceived ideas or assumptions of the survey designer.

Well-made surveys require trained and experienced personnel to develop.

Development time can be significant.

5. Conflicts and inconsistencies in information from stakeholders require additional analysis to resolve.



+What’s a user story

• As a user/stakeholder ...

• I want to … achieve a goal

• So that I can … get some value



+How to guaranty quality of requirements

Stories should be I.N.V.E.S.T:Independent – Negotiable– Valuable

Estimable – Right Sized – Testable

But also :Unambiguous – Complete – Verifiable –

Consistent – Modifiable - Traceable


+Complete

Inclusion of all significant functional and non-functional requirements Specification of the responses to valid and invalid input

values Conformity to any standard that applies Full labeling and referencing of all figures, tables, and

diagrams and definition of all terms and units of measure Any RD&S that uses the phrase to be determined (TBD) is

not complete


+Unambiguous

Every requirement has only one interpretation

Each characteristic is described using only one term

Example of ambiguous requirement: All customers have the same control field

a) All customers have the same value in their control fields

b) All customers control fields have the same format

c) One control field is issued for all customers


+Consistent

No set of individual requirements conflicts

Examples:• One requirement might state the format on the output

One requirement might state the format on the output : a field is report as tabular, but another as textual


+Modifiable

Necessary changes to the requirements can be made easily, completely, and consistently

Coherent, easy-to-use organization – table of contents, an index, explicit cross-referencing

• Not be redundant


+They want it all: ask your customer

How fast should the service/product perform?

How available should the service/product be?

How about security?

— As fast as possible!— 24 x 7 x 365!— Everything should be secure!


+

Customer: We want to have 100% system uptime.

Architect: OK, that might be doable, but requires all components to be redundant and eligible for automatic failover. That would take a year and $1,000,000 to implement.As an alternative, we can build a simpler system for $500,000 in 8 months but it will require manual maintenance in case of failure. Which one would be more suitable for you at this point?

Customer: Let’s build the second option, it’s much cheaper and faster. We’re a startup and time-to-market is our top priority.


+Wouldn’t you?

Speak to stakeholders in their own language.

Explain the tradeoffs in terms of cost, schedule, and realism.

Together, try to come up with specific, measurable NFRs.

Prioritize: the domain matters a lot!


What are Non Functional Requirements

“Functional requirements define WHAT a system is supposed to do”

“Non-Functional requirements define HOW a system is supposed to be”


+Knowing of non-functional requirements

Helps to avoid of customers say

„You should thing better!“


+Non-functional requirements are aspects

• Users have implicit expectations about how well the software will work.

• These characteristics include • how easy the software is to use,• how quickly it executes,• how reliable it is,• and how well it behaves when unexpected conditions arise.

• The non-functional requirements define these aspects about the system.


+Non Fuctional Requirements - General

• Security• Exception Handling• Validation• Logging• Tracing / Testing• Monitoring / Reliability• Transaction• Storage• GUI Binding• Configuration


+ Non Fuctional Requirements– System / Dev

• Naming conventions• Caching, Performance• Scalability• RAM usage• Thread Sync


+ How to fetch non-functional requirements?

• Anti-stories are things the user does not want to happen, commonly for safety or security reasons.


+Security

- Should access to be limited?

- Is an access list necessary?- Access Control List- White List- Black List


+Exception handling

- What errors can occur on runtime?

- What it should do in case of error?


+Validation

• Which input items are required?

• Which of them need to be validated?

• What to do if input is invalid?

• How to recognize if an item is valid? (email, personal number, ZIP code...)

Be aware - customer tends to change it frequently!


+Logging

• It is about loggin from the user perspective, not developer’s logging

• Which events should be logged?

• Which items should log contain?

• Is the last operation enough or you need history?• How deep the history should be?

• Where to log? (file/db/…)

• Who should have access to logs?

• Incremental or rotation log?

• How to purge/delete logs?


+Tracing - testing

• How to test an application?

• Which parts of the application should traceable?


+Transaction

• Which operation is „atomic“- what must be proceeded all at once?

• How to do rollback/cancel an operation?


+

Satisfied

Dissatisfied Neutral Don’t

careDissatisfie

d

If I didn’t have this …

If had this …

Making decisions on features



+How to manage requirements?

Fundamental Needs - Usages scenarios

Requirements linked to the usage

Constraints

Priorities

Main Needs

Specific requirem

ents linked to the need

Level of

required

performance

Measures and

tests to verify

that de delivera

ble

MoSCoW Status



+

Must Have

Could Have

Should Have

Won’t Have

Use MoSCoW to prioritize requirements !

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Requirement 1

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Requirements

Education

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