Here’s a fun experiment for you to try: Ask 10 designers whether or not they believe design principles are important. Odds are they’ll all answer with a resounding “Yes!” In fact, you’d be hard pressed to find anyone at any level of product development who would argue that design principles are a bad thing. Just about everyone will agree that they're important in order to maintain product quality and consistency … but that seems to be where the agreement ends. While you’ll find a consensus that design principles do matter, now ask those same 10 designers why and how they matter. This time, you’re likely to receive 10 different responses.

This kind of rampant disagreement is odd when you consider what Debbie Millman wrote in How to Think Like a Great Graphic Designer: “Design is one of the few disciplines that is a science as well as an art.” As a science, shouldn’t there be some objective truth, methods, and processes when it comes to design? Well, it turns out there are -- but to understand how to apply that means seeing the bigger picture and the way that design fits into the puzzle.

First and foremost, design principles are necessary in order to onboard new designers and make sure everyone is on the same page, working towards the same goals. “New” in this context doesn’t necessarily have to mean junior designers -- though it can. Here though, “new” means anyone, at any level, who is new to your company, team, or project.

After all, different projects within a team or company can require slightly different design principles. Take Google -- while all of the their products conform to their core company-wide material design principles, individual products, such as the Pixel phone, for example, each require a unique set of principles that will best serve the product. To put it another way, project-specific principles will align with and flow from team-wide principles, which in turn will flow from company-wide principles.

Go With The Flow

Likewise, while it may not seem obvious at first, design principles at any level should flow from and align with your culture, your mission statement, and your core values. After all, at every level of your company, you should be focused on the need(s) you’re filling for the customer, what job you are helping them do, what problem you’re solving for, and how you’re helping them make progress -- in short, how and why you’re helping them succeed. Your mission statement should encapsulate why your company cares about solving particular problems for your customer. The products you offer them are the tangible proof that you’ll do it. Your product is the delivery on your promise.

Design principles, then, shape the product in a crucial way. They convey your message out in the world. They form the evidence of what you’re going to do for the customer and the need you’re going to solve for. They speak through the product directly to the consumer. And in order to have a productive conversation with your product, customers must find value in it if you expect them to use it -- and continue using it.

As we’ve discussed elsewhere, there are three necessary components to get someone to perform a target behavior: motivation, ability, and a trigger. In the product world, the target behavior for your customers is to to use -- and continue to use -- your product. Your customer’s motivation is their need to solve a problem. It’s why they would use your product. They will solve this problem by using your product, as long as your product gives them them the ability to do so, without obstacles and barriers to their progress. And the trigger is what happens right before they use it -- that moment in time that causes them to say, “I need to use this right now, to solve this problem, to do this job.”

And so, to understand how to convey this value in your product through design, you must understand why customers would want to use your product in the first place. And to understand that, you must be clear on what job they are hiring your product to do. As Clay Christensen explains in Competing Against Luck, “When we buy a product, we essentially ‘hire’ something to get a job done. It it does the job well, when we are confronted with the same job, we hire that product again. And if the product does a crummy job we ‘fire’ it and look around for something else we might hire to solve the problem.”

Your design principles shape the product and in turn serve the customer. They are what will facilitate the customer’s ability and motivation to use your product -- or not. Ultimately, your design principles should answer these questions for the consumer: “Why would I hire your product? And why would I continue to use it?” Every design principle needs to serve this goal.

Getting Practical

Now that we’ve talked about why design principles matter, we come to the question that underpins practicalities of getting started: Um, what makes for great design principles? Once you understand just how necessary they are in order to convey the value of your unique product and the job it will do, you can see that it really isn’t, by definition, a matter of opinion. 

Design principles, unequivocally, must be specific -- not broad. User Interface Engineering founder Jared Spool explains the importance of specificity, based on his observations of how teams benefit (or don’t) from their design principles: 

As we looked at the teams getting the most from their principles, we found these were more detailed, more specific than just one word attributes, like 'innovative.' They were talking to the very things that would make this release different, better than anything they or their competitors had produced before.

Great design principles, then, are unique to your product and your product alone. And that makes sense, because to be competitive they can’t be principles that could be cribbed by another company. After all, if you’re filling needs no one else has filled, or filling one 10 times better than anyone else, then no one is doing precisely what you do. Since only you are creating this unique solution to a problem, only you could create your own specific design principles to serve this goal.

Check out "Design Principles: Moving From Broad to Specific" for a more in-depth discussion about what makes a design principle great, as well as some examples of great ones.

When thinking about your design principles, there are some other important distinctions to keep in mind: They should never be confused with best practices or marketing fluff. By definition best practices are universal -- they could apply to any company or any product. As such, they can’t possibly be design principles, which need to be specific and unique to your product. Unfortunately, people do conflate them from time to time, and in so doing lose their product’s unique value and identity, as we discuss here.

Marketing fluff masquerading as design principles is all about style over substance, as we discuss here. Fluff reads like catchy product slogans you’d see in a magazine or on a billboard: They sound great, but when you think about them, or try to apply them, they aren’t really meaty or actionable.

But if you avoid these design principle pitfalls and go forth armed with a true understanding of why design principles matter and how to create a great set for your product, you’ll be able to maximize your competitive advantage and convey your value to the customer through design.