Over the last few years I’ve been working on a set of guidelines that both my team members and students can use to help judge if a product is well designed.

I owe a great debt of gratitude to Dieter Rams and Ben Shneiderman for their work putting down design principles, as well as Don Norman and many others who have written thoughtfully about design. I wanted a set of design guidelines that could bridge digital and physical product design, as so many products rely on both diciplines. I created this set of principles that can work for a variety of product design situations, and would take into account our modern, interconnected world.

No product is an island. Good product design acknowledges that. Many principles are high-level precepts to keep in mind when building a product. I wanted something that could accomplish that while also being a check list of important considerations during product design and development.

You can use the below guidelines to check if your product is ready to ship (or if your prototype is being thoughtful enough), and you can use it as a core way to critique other products.

Not all guidelines will apply to all situations. I encourage you to combine this with other guidelines and methodologies and to find the right mix for your work.

We use these guidelines in our product critiques. Here is my design critique rubric.

This is version 1.0, and I intend to update these as needed.

Here are my Guidelines for thoughtful product design

Users are engaged with during the design process
It’s not user-centered design or user experience, if users aren’t involved. We should engage with a diverse set of users and seek to understand their problems. Beware of accidentally designing for symptoms instead of problems. Initial problems are usually symptoms and further probing and research will be needed. Also be careful not to ask users what they want built. Our role as designers is to discover their problems and to create thoughtful solutions.

Design for actions, not individuals
Design for actions and your product should be useful for a lot of people. Design for individuals, or even tasks, and your product may be too narrowly tailored to how only some people think. Design for an individual, and your product may only be well-designed for that individual.

Affordances are easily discoverable and understandable 
Affordances help users understand what is possible and help users utilize a product, but they are not effective at that if they aren’t both discoverable and understandable. With connected products, effective layering of affordances becomes important, such as smart lightbulbs that can be controlled by voice, touchscreen apps, and wall physical switches.

Signifiers should not be used to cover up for poor affordances
Not all affordances can be perceived or properly understood on their own, and signifiers play an important role in helping to make affordances understandable. Signifiers are often more important than affordances, but they should not be band-aide signifiers that cover up for poorly conceived and confusing affordances. Layering of signifiers is often critical, such as buttons on a smartphone app having both and an icon and descriptive text.

Features are easily discoverable and understandable
Discoverability and understanding are two key concepts of good product design and are core concepts of usability. Good products have both. If a user can’t discover a feature, it doesn’t exist for that user. Users should be able easily discover features without instructions, and once they do discover a feature, they should be able to quickly understand how it works and why to use it. If a user can’t understand how to use a feature, it also doesn’t exist.

Little to no training is required
A product that requires a lot of training probably has significant usability issues. A well-designed product should not require lots of training or for users to read manuals to make sense use of a product. Users should be able to easily learn how to use your product. Even complex, non-consumer products can be — and should be — made approachable.

Product has a high degree of utility and doesn’t exist for the sake of existence
A product can be very usable, and yet still not be very well designed if it doesn’t have much utility. It’s not enough to make usable products; we have to make products that people want to use.

Product has high-degree of functional integrity and is largely free of defects or bugs
A product that is otherwise well designed with high usability and utility, but has functional integrity, fit and finish, and bug issues is in fact not well designed. A product has to reliably work for it to be well designed.

Product is memorable
Once users learn how to use a product, they should be able to remember it. Users should be able to go days, weeks or even months inbetween using a well-designed product and be able to pick up where they left off. A poorly-designed product will require frequent retraining. A product that is easy for someone to pick up without training will be memorable.

Internal and external consistency is observed and achieved 
A well designed product is both internally consistent with itself and externally consistent with other products from the same company.

Product fits into a larger ecosystem seamlessly
Ecosystems exist not only within companies and product lines, but also within the wider world. A modern product should be well-designed from an ecological perspective in both instances. Every product is part of a larger ecosystem, and should be designed as such. You could develop an incredible next-generation smartphone, for instance, but if it was not chargeable by standard electricity and wall outlets, it would not fit within the larger established ecosystem.

Product is free of extraneous or superfluous features
Design is about making choices. Extraneous and superfluous features will distract and confuse users ability to use other, more important features.

Product is edifying to use and visually and tactilely pleasing
A well-designed product is enjoyable to use and interact with. People should get pleasure from using your product. People should want to use your product.

Product is persuasive
It encourages you to use it and complete primary actions. Users should be able to understand calls to action and be persuaded to do them.

Users are given proper warning before committing destructive actions, and destructive actions are reversible 
Destructive actions can be empowering for a user, but they can also be committed in haste or by mistake. Users should be given proper notice and feel like they gave informed consent before committing a destructive action. Even so, destructive action should be reversible, even if only for a short time. The actions should be easily reversible by the user and should not require a support call.

Error-handling should be clear and intuitive 
A well-designed product should rarely allow a user to commit an error, but with digital and connected products becoming more complex, errors will happen. When a user gets an error, error message should be clear and written in concise, humanistic language. When a system throws an error it shouldn’t erase everything a user just done.