Software Engineering basics - Mutable Requirements

In Software Engineering, mutable requirements are requirements that are likely to change during the software development lifecycle. Unlike stable requirements, mutable requirements are not fixed at the beginning and may evolve due to changes in technology, business needs, regulations, or user preferences.

1. Definition

Mutable Requirements:

Requirements that are dynamic and subject to change during the development process.

2. Characteristics

  • Uncertain or evolving: Often arise from areas where business rules, user needs, or technology are not fully defined.

  • High impact: Changes can affect system design, architecture, or implementation.

  • Need careful management: Typically managed using iterative or agile approaches.

3. Examples

  1. Business Rules:

    • A company may initially require a simple online payment method, but later decides to add digital wallets, UPI, and crypto payments.

  2. User Interface (UI) Preferences:

    • Users may request different layouts, color schemes, or interaction styles after seeing prototypes.

  3. Regulatory Changes:

    • A software product for healthcare may need updates if new compliance rules are introduced mid-development.

  4. Performance Expectations:

    • Initially, response time may be specified as 2 seconds, but stakeholders may later demand 1 second for better UX.

4. Handling Mutable Requirements

  • Use iterative development models like Agile or RUP.

  • Maintain a change management system to track modifications.

  • Prioritize changes based on business impact and feasibility.

  • Communicate changes clearly to developers, testers, and stakeholders.

Summary

Mutable requirements are flexible and subject to change due to evolving business needs, technology, or user feedback. They require careful management and iterative development approaches to ensure the system adapts without excessive cost or delay.