The Art of Agile Development, 2nd Edition

Ubiquitous Language

AUDIENCE

Programmers

Our whole team understands one another.

Try describing the business logic in your current system to a domain expert. Can you explain it in terms they understand? Can you avoid programming jargon, such as the names of design patterns, frameworks, or coding styles? Is your domain expert able to identify potential problems in your business logic?

If not, you need a ubiquitous language. It’s a way of unifying the terms your team uses in conversation and code so that everybody can collaborate effectively.

The Domain Expertise Conundrum

One of the challenges of professional software development is that programmers usually aren’t experts in the software’s problem domain. For example, I’ve helped write software that controls factory robots; directs complex financial transactions; analyzes data from scientific instruments; and performs actuarial calculations. When I started working with those teams, I knew nothing about those things.

It’s a conundrum. The people who understand the problem domain—the domain experts—are rarely qualified to write software. The people who are qualified to write software—the programmers—don’t always understand the problem domain.

Overcoming this challenge is, fundamentally, an issue of communication. Domain experts communicate their expertise to programmers, who in turn encode that knowledge in software. The challenge is communicating that information clearly and accurately.

Speak the Same Language

Programmers should ...