Establishing Requirements (User Requirements)

Four basic activities in Interaction Design:

1. Identifying users, their needs and requirements
2. Developing alternative designs
3. Building versions of the designs
4. Evaluating designs

Requirement Analysis

The specification activity defines the behavior of a system in development and determines the method for requirements documentation (Natural language documents, Process models, Business definitions, Use cases, User stories or Process specifications).

Establishing what the customer requires from a software system.

What Is a Requirement?
A requirement is a kind of a statement of something the system must do like an external behavior of a system or of a constraint under which the system must work. Requirements arise from understanding users’ needs and can be justified & related to data too.

Different types of requirements

• Functional Requirements
• Non Functional Requirements
• Data Requirements
• Environment/Context
• User Requirements
• Usability Requirements

Functional Requirement (Function)

A Functional Requirement is a requirement that, when satisfied, will allow the user to perform some kind of function.

Example: “The customer must place an order within two minutes of registering”

Functional Requirements have the following characteristics:

• Uses simple language
• Not ambiguous
• Contains only one point
• Specific to one type of user
• Is qualified
• Describes what and not how

Non-Functional Requirement

A Non-Functional Requirement is usually some form of constraint or restriction that must be considered when designing the solution. 

Example: “The customer must be able to access their account 24 hours a day, seven days a week.”

Data Requirements

Part of the application design process is identifying required data, as well as any security issues surrounding access to that data.
Example :

• What kinds of data need to be stored?
• How will they be stored (e.g. database)? 

Environment/Context

Environment and Context requirements defines the physical social and organizational requirements.

• Physical

          Example : Dusty? noisy? vibration? light? heat? humidity? 

• Social 

          Example : Sharing of files, of displays, in paper, across great distances, work individually,

          privacy for clients

• Organisational

          Example : Hierarchy, IT department’s attitude and remit, user support, communications structure and

          infrastructure, availability of training

User Requirements

User requirements define who are the users that is going to use the system, characteristics and the system usage ability as well.

• Characteristics: ability, background, attitude to computers
• System Use: novice, expert, casual, frequent

Requirement Analysis Table For The Monday Clinic Application Prototype

Requirements	Requirement Type	Priority	Validated By Client	Obse -rvations
Keep an eating diary	Functional Requirement	High
Keep an exercising diary	Functional Requirement	High
Midwives to monitor clients progress	Functional Requirement	High
Access to the healthy food recipes	Functional Requirement	Medium
Access to further relevant information	Functional Requirement	Medium
Tools- Shopping List	Functional Requirement	Medium
Client to visualize progress	Non-Functional Requirement	Medium
Client to achieve a maximum weight gain of 7KG	Business Requirement	High
Community of users	Functional Requirement	Medium