Formal Specifications vs Informal Specifications

Developers should learn formal specifications when working on safety-critical or high-assurance systems where errors can have severe consequences, such as in avionics, automotive software, or blockchain protocols meets developers should learn and use informal specifications when collaborating with non-technical teams, such as clients or business analysts, to quickly capture and refine requirements before detailed design or coding begins. Here's our take.

Formal Specifications

Nice Pick

Developers should learn formal specifications when working on safety-critical or high-assurance systems where errors can have severe consequences, such as in avionics, automotive software, or blockchain protocols

Pros

• They are valuable for specifying complex requirements precisely, detecting design flaws early through model checking or theorem proving, and facilitating formal verification to prove system properties, reducing bugs and improving trustworthiness
• Related to: model-checking, theorem-proving

Cons

• Specific tradeoffs depend on your use case

Informal Specifications

Developers should learn and use informal specifications when collaborating with non-technical teams, such as clients or business analysts, to quickly capture and refine requirements before detailed design or coding begins

Pros

• They are particularly useful in agile or iterative development environments where flexibility and rapid feedback are prioritized, helping to align expectations and reduce misunderstandings early in the project lifecycle
• Related to: requirements-engineering, agile-methodologies

Cons

• Specific tradeoffs depend on your use case

The Verdict

These tools serve different purposes. Formal Specifications is a concept while Informal Specifications is a methodology. We picked Formal Specifications based on overall popularity, but your choice depends on what you're building.

The Bottom Line

Formal Specifications wins

Based on overall popularity. Formal Specifications is more widely used, but Informal Specifications excels in its own space.