A Matter of Principle

Surfacing the core truths in every design

Julie Zhuo
The Year of the Looking Glass


A thousand decisions go into every design.

What’s the primary view of the app? How should someone navigate the different options? What color should the top bar be?

A good designer will have a logical answer for each decision. Nothing should be done at random, after all, and intentionality is a hallmark of good design.

The primary view of the app is a table view of messages, because that’s what people most want to see when they arrive.

We have four main views in this app, so a tab bar is an easy way to make these views discoverable.

We don’t want the top bar to be too loud, so that’s why it’s white.

A good designer will make you feel like you can ask her about any of the decisions she made, and you’d get a clear answer.

Unfortunately, this isn’t particularly scalable. If I want to understand even a fraction of your thousand decisions, we’d be talking until the cows come home.

That’s the difference between a good designer, and a great one.

You see, a great designer starts with the whys. She conveys the principles behind her thinking and leaves you feeling like you understand the core values from which all her design decisions flow.

Principle (noun): a fundamental truth that serves as the foundation for a system of belief or a chain of reasoning.

I’ll be honest with you. I used to be the biggest skeptic of the whole “list of principles” thing. Whenever somebody would begin their design presentation to that effect, I’d lean back in my chair and think, “great, a barrage of words designed to induce head-nodding.” I wanted to jump into the meat of the thing and talk about the actual designs.

I shouldn’t have written off how useful a set of words can be. But the fact is, it is hard to come up with good ones.

Our design should be simple.

Our design should be self-explanatory for our audience.

Our design should be pleasing to look at.

Like anyone is going to raise their hand and say, Actually, I’d rather our designs be complex, require an instruction manual, and offend the eyes, thankyouverymuch. Principles that feel too broad or obvious might as well be meaningless. They don’t help shed any light on downstream design decisions. They don’t help get people on the same page around what’s important.

A good set of design principles, on the other hand, does the following:

  1. Helps resolve practical and real-world questions around specific design decisions.
  2. Applies to an entire class of design decisions, both things we can think of today, as well as questions that will pop up in the future.
  3. Imparts a human-oriented sense of “why?” that is easy for everybody — including non-designers — to understand.
  4. Has a point of view and a sense of prioritization that a rational person could disagree with.
  5. Is generally paired with illustrative examples that show how the principle applies to specific decisions.

Looking for examples? Apple’s Human Interface Guidelines or Google’s Material Design Guidelines both do an excellent job of explaining the rationale behind their design systems. They’re also a prime example of how influential good principles can be. If you imagine that Apple and Google’s end goal is to ensure developers make high-quality apps that feel at home on their platforms, then one route they could have taken is to have their design teams meet with and give feedback to all the major apps on their platform. That’s the same as two designers trying to talk through each of a thousand decisions on any particular design. It’s not unsustainable.

Instead of relying on gatekeepers to keep a high quality bar, better instead that everyone gets to agreement on a smaller set of guiding values, so that the best decisions get made in a consistent manner, scaling across many decisions, and even many designers.

So the next time you share your designs, or — better yet — even before you sit down to design, spend some time defining your principles.

The most important thing we believe is that the act of communicating with someone should feel lightning fast, with as little friction as possible.

In order to achieve that, we adopt familiar system design patterns, so people don’t have to learn anything new — standard table views, tab bar navigation, etc. We don’t try and distract from the a person’s experience with bold colors or quirky animations. For common things a person may want to communicate, we strive to make them inline and doable in one or two taps.

Good principles are solid. There is a weightiness, a certainty behind them. What looks right, what feels good — these are superficial things. A great designer defends her work based on principles that last, past one decision, past a thousand, that aren’t carried by whichever way the wind blows.



Julie Zhuo
The Year of the Looking Glass

Building Sundial (sundial.so). Former Product Design VP @ FB. Author of The Making of a Manager. Find me @joulee. I love people, nuance, and systems.