How Design Principles Drive Excellence at Scale

At Source.paris, we're always thinking about what makes good product design. We believe it's a mix of creativity, understanding users, and having a clear strategic vision. But how do you ensure consistency and excellence across a growing team and complex projects? That's where Design Principles come into play.

We've been working with BNP Paribas for almost a decade now, supporting them on Product Strategy, Product Design and Design at Scale. Most recently, we helped them establish and deploy Design Principles in their French retail banking branch.

What are Design Principles?

Some of the most famous Design Principles are Dieter Rams' Ten Principles of Good Design. They were developed in the 70s while he was Chief of Design at Braun.

Since Design is inherently subjective and challenging to quantify, Rams attempted to provide a framework to assess one simple question: Is my design good design?

Although Rams' principles were originally applied to industrial design and physical objects, they remain highly relevant in designing digital products, services, and experiences.

In our context, for a design team or an organization, Design Principles create a framework for decision-making. They are fundamental guidelines that shape our approach to design. These principles should be clear, memorable, and actionable, reflecting the values and vision of the design.

Design Principles are useful because they represent:

• A unique design philosophy

• A common language for the team

• A tool for alignment and consistency

• A top-level structure that gives meaning to guidelines

• A mnemonic device

• A support for effective peer reviews

The aim of Design Principles is to inspire designers without imposing rigid boundaries.

Importantly, they are not:

• Inflexible rules

• Generic best practices

• Marketing manifestos

• Substitutes for creativity

• Replacements for guidelines

• Standalone tools

Why are Design Principles essential in Design teams and organizations?

Clearly defined Design Principles offer numerous benefits:

• Ensuring consistency across projects: Large organizations often work on diverse projects for various products. Design Principles help maintain a consistent quality and user experience across these different engagements.

• Facilitating communication and collaboration: Principles provide a shared vocabulary and understanding among designers and stakeholders, streamlining the design process.

• Guiding Design decisions: When faced with choices, Principles offer a framework for evaluation, justification or defense of decisions, ensuring that choices are aligned with the overall strategy and design goals.

• Improving Design quality: By focusing on core values and user needs, Design Principles elevate the quality and effectiveness of the final product.

• Onboarding new designers: Principles help new team members quickly understand the team design values and approach.

• Concrete example: BNP Paribas BCEF

We've had the privilege of working with BNP Paribas BCEF (Banque Commerciale en France) for many years, witnessing their commitment to evolving their digital products.

With the agreement of their design team, we're going to share how it all went down.
A special thanks to Delphine Zamparini (Design Manager) and Elisabeth d’Erceville, (Head of Design) for their trust!

In just a few years, their team grew from 5 to 30 designers. The more people joined, the harder it became to keep the product experience consistent without relying too much on a few key members.

“As our team scaled, it became essential to spread our design convictions across the department and beyond, in order to ensure long-term design quality.”
- Elisabeth d'Erceville, Head of Design at BNP Paribas BCEF

As part of their Design Excellence program which involves clarifying quality standards, implementing tools and structuring processes, BNP Paribas embarked on a journey to define their Design Principles. This involved several key phases:

1. Observation of market practices and collection of prerequisites:

   • Familiarizing with Design Principles of mature players (Apple, Airbnb, Braun, Facebook)

   • Evaluating BNP Paribas BCEF's existing guidelines and Design System uses

   • Collecting feedback and identifying recurrent design errors

2. Analysis of the expected role of design:

   • Reflecting on the role and missions of the design organization in its current state and future aspiration

   • Identifying fundamental values of the BNP Paribas brand

   • Formulating initial principles necessary to limit repetitions in peer reviews

3. Formalization of the first Design Principles:

   • Training the team

   • Iterating on the principles

   • Documenting examples of current application

   • Creating recruitment exercises

This work resulted in the creation of 6 Design Principles that align with and support the company's overall strategy. These principles guide high-level decisions and direction.

Application of Design Principles

As mentioned earlier, the aim of Design Principles is to inspire designers without imposing rigid boundaries. But where do they fit in, and what priority do they take when we already have other existing design documentation?

We developed a three-level pyramid, each with its specific role

1. Design Principles (vision and values)

2. Guidelines & foundations (concrete translation into rules and best practices)

3. Components (library of reusable elements)

This structure not only helps to clarify the responsibilities of each element but also ensures a smooth transmission of intentions from vision to implementation.

Deployment Strategy

The deployment of Design Principles intends to standardize practices by guiding daily design decisions, ensuring consistency, facilitating recruitment, accelerating validation, encouraging innovation, and serving as a reference for design evaluation.

To achieve successful organization-wide adoption, BNP Paribas is following this strategic sequence.

Validation with top managers: Securing strong support and refining the principles to fit organizational challenges.

• Presenting and iterating with lead designers: Gathering feedback and ensuring buy-in from key design leaders

• Training teams through practice: Utilizing interactive methods like Kahoot to increase engagement and reinforce knowledge

• Reinforcing adoption: Integrating principles into daily workflows through quizzes, case studies, and accessible documentation

• Diffusion outside the design department: Communicating the principles through visuals, events, and stakeholder involvement

First results and moving forward

The journey of diffusing Design Principles is still ongoing but is already showing promising results. Currently, over 20 designers have participated in training, with a survey showing that the initial full-day training scored 4.5 out of 5 in terms of usefulness for their daily work.

Designers now ask more profound questions, develop more refined solutions, and move beyond subjective 'I like/I don't like' feedback to a more systematic approach to design.

The focus now evolves to further strengthen the impact of design on strategy. A critical next step in this evolution is the acculturation of stakeholders across the organization (IT, Business, Product Management) to Design Principles and practices.

If you want to discuss how Design Principles, or our Design at Scale practice, can elevate your work, feel free to reach out at hello@source.paris.