Making decisions is what designers do regularly when designing products and services. Some of these decisions are straightforward (e.g., where to place the Log in button), but others require choosing between two competing goals. For example, should we go for a clean, minimalistic design or make content super discoverable? Which user group should we prioritize for this task: power users or casual users? When faced with tradeoffs like these, designers need to choose which goal to sacrifice in favor of another. Doing so can be tricky: the choice made can feel subjective or random and can result in lengthy — and possibly unneeded — debates within large design teams.

One useful device to guide designers to make the right tradeoff decisions are product-specific design principles. These principles support consistency in the way decisions are being made across teams, build confidence in the decision, and eliminate fruitless debates.

Definition: Product design principles (or, in short, design principles) are value statements that describe the most important goals that a product or service should deliver for users and are used to frame design decisions.

It’s worth stating that product design principles are different from principles of good design, such as usability guidelines, heuristics, or visual-design principles. Design principles are specific to the product or service that is being designed. That being said, they are not directions on how to design specific UI elements (like design patterns or standards). Often, product design principles are referred to as ‘design principles,’ and usually, the context is enough to understand whether the term refers to general UI principles or to product-specific design principles. In this article, we use “design principles” and “product design principles” interchangeably.

To illustrate how design principles work, let’s have a look at an example. Here’s a design principle for Nielsen Norman Group’s website.

Clarity Over Popularity

We’re not an academic journal, nor a trendsetter. Our goal is to be a source of clarity and instruction, and to provide actionable advice for UX professionals that’s backed by research.

Practitioners today come from many different backgrounds and UX isn’t easy; it’s nuanced and complex. Let’s give users advice that’s clear, easy-to-digest, and concrete without introducing unnecessary jargon or confusing terminology. By doing so, we can empower designers to succeed in their jobs and make the world a better, more user-friendly place.

In order for design principles to be effective, they should:

  • Take a stand on which value is important: Each principle should be clear on what value it advocates and why. If the principle is ambiguous about what it recommends, then it could be interpreted differently. It can be helpful if a value is explicitly called out over another regularly conflicting value to make the desired choice more obvious.
  • Inspire empathy: A design principle should mention why that value is important to users. By doing so it helps designers keep users at the heart of their design decisions.
  • Be concise: Design principles are not meant to be an essay. Keep it short and to the point, to ensure they’re easily understood, referenced, and remembered.
  • Be memorable: If you have content specialists in your organization, it’s worth getting their input in drafting principles to make them memorable (as well as concise). Additionally, you shouldn’t have too many. For example, having 10 or more leads to many being forgotten; reading and understanding them again each time they are needed consumes too much time.
  • Not conflict with one another: Each principle should be dedicated to one value only. However, be careful that your principles don’t conflict. For example, if there was a principle about consistency and another one about adaptability, then it would be difficult to understand how these values should be prioritized against one another when faced with a design decision that requires sacrificing one for the other. If both are important, but in different contexts, then clearly specify in which contexts one of these principles is more important than the other.

Writing effective design principles is harder than it sounds. However, there are plenty of good — and not so good — examples out there that can be used to draw inspiration from. (It might also be interesting to check your competitors’ design principles!) If you’re thinking of writing some design principles for the first time, here are some simple steps which you can perform alone or in a workshop with your team and stakeholders.

Step 1: Identify Core Values

Before writing your design principles, you need to identify the values essential for the success of your product or service. These important values may have been captured in vision statements or project briefs. If these don’t exist, then do some research; find out what differentiates your product or service from your competitors’. Why do people choose to use your product or service, and not a competitor’s? These values might be those to emphasize in your design principles. If you have many, then prioritize the ones that are most important overall for the success of the product or service.

Step 2: Consider How These Values Impact Users

To ensure you write design principles that are user-centered, ask yourself: why are these values important? What do they help to achieve for users? If we didn’t pursue them, how would our users be affected? Write these out.

Step 3: Identify Any Common Tradeoffs

Are there any well-known, simple conflicts in your organization that should be settled? If so, call them out. For example, you might have a frequent conflict between the needs of sellers and the needs of buyers on an ecommerce platform. If their needs conflict, which user group should be prioritized?

Step 4: Write, Compare, and Iterate

Having many people write a version of a design principle for each value can help to generate many good ideas. Voting can reveal a favorite, or all versions could be blended to produce a principle that everyone has had a hand in creating.

It’s a good idea to involve others in the creation of design principles, as they will be more likely to be accepted and adhered to. It is also a great way to set focus before building a new product or service or when onboarding new designers.

After producing design principles, ensure they’re not forgotten. Publish them in blogs or with your design system, regularly discuss your design principles in meetings, include them in presentation decks, or print them and stick them up on walls so designers know about them and can easily reference them. Most important, use the principles to explain and justify design decisions: when you make a trade-off decision, don’t just say, “we’re doing it this way because I say so” (or, “because it’s best” which is just a nicer way of saying the same). Say that we’re doing it because principle #3 tips the balance in favor of one of the options.

Conclusion

Design principles help to keep important values front and center in the design process. When successfully composed and used, design principles ensure consistency in decision making across designers and teams, removing the need to debate simple tradeoffs and letting designers worry about complex problems.

Learn more about design principles in our class on Design Tradeoffs and UX decision frameworks, a full-day course at our UX conference.