INNOVATING DESIGN PRACTICE
How design thinking, design goals, design principles, design heuristics, design language, design patterns, design systems, and design execution relate. Oh my!
What is the difference? Why does it matter? When does it matter? Where do I use them? Who cares?
Design Thinking is a process that any team can use to come up with innovations for their business, product, or process. Conceived in the early 1960s, popularized in the 1990s, and “diluted” in the 2000s design thinking is a tool that businesses use when they want their company or team to be more “innovative.” 
Design Thinking provides a framework for innovation. Often teams do not have tools for finding and evaluating new opportunities. Design Thinking offers a process that teams can follow to explore and develop new directions.
Design Thinking can be used for strategic direction within an organization or down to teams finding direction within a project. The important thing about doing a design thinking exercise is to scale the time appropriately to the needs of the research and development needed to attain a meaningful result.
The rest of these Design [WORD] phrases are design-team specific but essential to design teams’ ability to be effective with other teams. Defining and promoting the following tools minimizes personal subjectivity and focuses conversations on what an organization considers meaningful.
Design goals, principles, and heuristics tend to exist on a continuum and are used interchangeably by some. This article provides a point of view for differentiating them.
Design Goals are statements a team makes about the quality of experience they would like a product to attain.
Design goals are targets for design work. — [John Spacey 2018]
Design Goals are used to make decisions when choosing among design options. Take efficient as a design goal. If three options are designed for a feature, the option that lets the user finish in fewer steps should be chosen over one that may be easier to learn.
When the team sets the goals, they should also set metrics for measuring whether the goal has been reached. They can either set quantitative goals like “User will be able to complete task 10% faster,” or qualitative goals like, “User feels the task is faster to accomplish.”
Design Principles are words or statements that set direction. Like design goals, they point to an expected result, but there isn’t an expectation of being reached. They are directionally correct but may never be reached.
Design principles are also used to make decisions. Depending on the priority of the principles, the team will pick the design that meets the most principles in the order of priority. As the arrows in the diagram indicate, some design principles take more effort (longer lines), and some are less important (not reaching the goal).
Design Principles have a continuum between table stakes like useful, usable, and consistent and those that drive differentiation or innovation, like trustworthy, approachable, or cinematic.
Sometimes priority will shift depending on the context of the feature. If a project had efficiency, trustworthy, and delightful as the design principles, prioritized in that order, you might apply them differently between login (+trustworthy) and the primary experience (+efficiency).
Where design goals and principles point to a specific outcome, design heuristics are strategies or “rules of thumb.” They articulate a general way to approach design.
Design Heuristics as a form of intermediate-level knowledge that may explain how designers build on existing knowledge of “design moves” — non-deterministic, generative strategies or heuristics — during conceptual design activity. [Gray 2016]
Often design heuristics are statements used to specify how to accomplish design principles or design goals (the design moves) — bold statement below.
- Trustworthy — be transparent about how the product calculates results.
There is some confusion between usability heuristics and design heuristics. Design heuristics are applied while creating the product. Usability heuristics are used to assess the product to see if it meets specific goals. The best-known usability heuristics are from Neilsen/Norman . They cover particular issues.
A Design Language is a set of precepts or general rules — usually formed out of Design Principles and characterized by Design Heuristics — that describe how you make decisions when designing a system. The priority of which guides teams on visual and interaction style choices. The strongest examples of these, such as Apple’s Human Interface Guidelines, Google’s Material Design, and IBM’s Design Language describe a company’s overall design philosophy as design principles, as well as how to apply them.
Design Principle — design heuristic.
- Trustworthy — be transparent about how the product calculates results.
- Approachable — don’t overwhelm the user with details, have the details unfold as the user shows interest.
- Cinematic — visual aspects and interactions should embody a sense of storytelling and richness.
Coming out of Christopher Alexander’s A Pattern Language, design patterns transitioned the idea of architectural patterns into the user experience design space.
Common user experience design patterns include such constructs as the shopping cart, carousel, search, and Cut, Copy and Paste on an Edit menu.
Every aspect of an experience that is used more than twice can be considered for a design pattern. Grouped into pattern libraries design patterns provide reusable components and then structures needed to build consistent experiences. This reuse and thus consistency lowers the effort to design by removing decisions about things that should be the same and focusing on what makes the experience unique. For users, the consistency design patterns enable reduces the cognitive load because similar experiences look and act the same.
Look for existing patterns outside of your company walls that users understand already…those might only be used once in your product, but achieve what you describe here for the very reason that they are familiar to new users of the product. — Jon Innes
Often design patterns come from outside a company, from existing products that have similar experiences. A company may appropriate these and then change the visual style to meet their company’s branding and add features to meet their users’ specific needs.
Read What is the Content of “Design Thinking”? Design Heuristics as Conceptual Repertoire  to see Design Thinking tied to Donald Schön’s relfective practitioner and Christopher Alexandar’s pattern language and design heuristics.
A Design System is the constructs or code that embodies a design language and its design patterns. Like design patterns, a quality design system starts a the atomic level — labels, fields, etc. and builds up to constructs like page templates, flows, and information architectures.
A design system is a bridge between design patterns and a developed experience. It is a kit of parts, made of code snippets that incorporate the visuals and interactions of the design patterns that engineering uses to quickly put together the common parts of an experience. This offloads repetitive development work and reduces quality assurance effort, leaving more time to concentrate on new and unique capabilities.
A design system will usually have a design specification — often provided from the design team as symbols from a program like Sketch, coded examples — so that engineering is reusing a consistent library, and usage guidelines to help designers and product management understand when to use what parts.
Why do these matter?
All of these constructs are to be used by design teams and the groups they interact with to more quickly reach consensus and execute the delivery of products that meet the users’ and the organization’s needs and goals.
Design [Words] are tools to help communication within the design team, and outside. They encourage critical, focused thinking on design issues. They can help educate outside stakeholders and create a common understanding/vocabulary (and they make us look smart). — Alex Carroll
Design Execution is the activities the design team takes to make sure a quality product reaches its audience. It encompasses the negotiations, support, and follow-through required to achieve for a pixel-perfect product.
More on that in an article for another day…
If decisions are doors to be opened and navigated through, design tools are the affordances that make decisions easier to open and navigate through — within a design team, between design teams, and between a design team, project management, and engineering. Make sure you are creating high-quality door handles. — KM
If you are interested in more about applying design practices to help your company innovate check out Designing for Innovation.
 Design Thinking: A Beginner’s Guide to the History, Terminologies, and Methodologies. Rhoda Sell. 2018.
 How do designers generate new ideas? Design heuristics across two disciplines. S. Yilmaz, S. R. Daly, C. M. Seifert, and R. Gonzalez. 2015.
 Design Heuristics: An Evidence-Based Tool to Improve Innovation. Seda Yilmaz, Shanna R. Daly, Colleen M. Seifert. 2014.
 10 Heuristics for User Interface Design. Jakob Nielsen. 1994.
 What is the Content of “Design Thinking”? Design Heuristics as Conceptual Repertoire. Colin M. Gray, Colleen M. Seifert, Seda Yilmaz, et al. 2016.
 Exploring Design Heuristics for User Interface Derivation from Task and Domain Models. Costin Pribeanu, Jean Vanderdonckt. 2002.