1. Topic 9: Requirements Definition and Prioritisation
Agile Development
Topic 9:
Requirements Definition and Prioritisation
NCC Education - Title Master

2. Topic 9 Coverage This topic will cover: What is a requirement?
Defining the requirements
Requirements in the Atern lifecycle
Requirements and modelling
The Requirement Lifecycle

3. What is a Requirement? Group Exercise
DSDM ATERN
Approach and Principles
What is a Requirement?
Group Exercise
List as many words or phrases as you can
that mean “requirement”.
ATERN S1 Approach 3

4. What is a Requirement? In simple terms, a requirement is a:
feature
function
service
constraint
that the solution needs to perform or exhibit.

5. Defining the Requirements
DSDM ATERN
Requirements Definition and Prioritisation
Defining the Requirements
Define a requirement along with its Acceptance Criteria as measurable targets at all levels.
Give it a unique ID
Keep details of:
source
owner
business benefit
priority
other?
Consider:
As a …I need … in order to …
ATERN S5reqdef 5

6. Functional Requirements
Functional requirement is “what”, not “how”.
Make it SMART
Specific
Measurable
Achievable
Realistic
Timely
Wording - functional requirement:
“We need the ability to …”
“As a … I need … in order to …”
Not in conflict with, or overlapping, other requirements.

7. Non-Functional Requirements
Non-functional requirements are about “how well” we do the functional requirements, i.e. with what:
security
availability
portability
maintainability
external interfaces
design constraints
performance
response time
etc. (see notes)
May be global or related to just one functional requirement.
May need extra time in the plan!

8. Structure of Requirements
Requirement Decomposition
Feasibility:
A very high level set of requirements is established
Foundations:
A high level set of prioritised requirements is established (a PRL)
User stories
Exploration and Engineering:
Each requirement may decompose into more detailed requirements
At some point, it may not need to be written down, but evolved as part of iterative development (prototyping)

9. Requirements and Modelling
Handle
Reservations M
R1.1
Make a reservation M
R1.2
Make a conference
booking W
Amend a reservation S
Make an individual booking
R1.1.1 M
R1.1.2
Cancel a reservation M
R1.1.3
Produce occupancy report C

10. Requirements in the Atern Lifecycle
DSDM ATERN
Prototyping, Timeboxing and Estimating
Requirements in the Atern Lifecycle
Less
Less
Outline
Plan
Delivery
Plan
Timebox
Plan(s)
Typically <10
requirements
Typically <100
requirements
Do not go into requirements detail too early
Requirement
Detail
Estimate
Accuracy
Do not be held hostage to early estimates
Typically >100
requirements
More
More
ATERN S7 Prototyping TimeboxandEst 10

11. What is MoSCoW? W C Must haves: S Should haves: M
fundamental to system
without them, system unworkable/useless
minimum usable subset
guaranteed to be developed
Should haves:
important requirements
would be mandatory, but workaround exists
system will still be useful/usable without them

12. What is MoSCoW? Could haves: Won't have this times: W
would add business benefit
more easily left out of this increment than Should Haves 
Won't have this times:
valuable requirements, but can wait until a
later increment
Note: All prioritisation is with respect to a clear project objective. M S C W

13. The Requirement Lifecycle
Each requirement must be subject to:
Elicitation
Workshops, model-building, interviews, observation, scenarios
Analysis
Realistic? Ambiguous? Combination of requirements? Aligned with business?
Validation
Prototypes, reviews, models, testing
Management
Traceability, stability, change management

14. Summary What is a requirement?
Functional and non-functional requirements
Requirements in the Atern lifecycle
Requirements and modelling
The Requirement Lifecycle

15. Topic 9 – Requirements Definition and Prioritisation
Any Questions?
NCC Education - End Slide Master