HKSM
Functional Specification
A defined capability or behavior the system or application must provide, typically documented in a functional specification.
Key Points
- States what the product must do from a user or business perspective, not how it is built.
- Each function should be clear, measurable, and testable with acceptance criteria.
- Supports estimating, design, development, and validation activities.
- Enables traceability from business needs to implemented features.
Example
On a payroll system project, the functional specification includes: "Calculate gross and net pay for hourly employees, applying overtime rules and tax tables." It outlines inputs, processing steps, and expected outputs used by developers and testers.
PMP Example Question
During planning for a new mobile banking app, which artifact should document required behaviors like "authenticate users with MFA" and "show real-time account balances"?
- Functional Specification
- Work Breakdown Structure
- Communications Management Plan
- Lessons Learned Register
Correct Answer: A — Functional specification that defines required system behaviors
Explanation: A functional specification captures what the system must do; the other options address scope decomposition, communications, or organizational learning.
