Which of the following is not included in the waterfall model?

Concept

A classical waterfall process organizes software development as a linear sequence of named phases. Each phase produces an output that becomes the input to the next phase, so phase membership is checked against that defined sequence.

Application

The commonly taught sequence moves through these activities:

1. Requirements analysis defines what the system must do.

2. System and software design specifies how the requirements will be realized.

3. Implementation, or coding, turns the design into program units.

4. Integration and testing check the assembled system.

5. Operation and maintenance follow delivery.

Requirement analysis, design, and coding therefore correspond to named activities in this sequence. Risk analysis is a risk-management activity and is especially explicit in risk-driven iterative models such as the spiral model, rather than a distinct phase of the classical waterfall sequence.

Cross-check and contrast

• Requirement analysis produces the specification that initiates downstream development.

• Risk analysis evaluates uncertainty and mitigation choices.

• Design produces architectural and component specifications.

• Coding produces executable program units from the design.

Result: Risk analysis.