Hello! This is Janneke Grootings, the driving force behind dim-sum. My purpose is to facilitate personal growth and better ways of working through creative strategy.

I’d like to introduce to you the Sum Collective, that I brought together to work together. We are a diverse, heartfelt group of independent thinkers and doers, who never settle for mediocrity. Who all rather work with people than for people. 

We share a focus on what matters most in our work: emotional and creative intelligence. A shared belief that this focus makes for more sustainable solutions brought us together. 

For every question – from people, brands, companies – we put together the smallest team possible, that can find the best solution simply, transparently and quickly.

We co-design sustainable change, gain insights and provide you with the strategic narrative to make them work for you. Also when we are not there.

— Janneke Grootings

The Sum Collective was born out of Janneke’s belief in mixing perspectives and disciplines, which is also reflected in her unusual background in HR, social sciences, editorial work, writing, branding, research and coaching. Her purpose is to facilitate personal growth and better ways of working.

With creative and narrative strategy she helps people, brands and organisations move with the times. By gaining insights, co-designing strategies and writing the strategic narratives needed to make them work. 

Themes: change, narrative strategy, coaching, design thinking, (editorial) communication

Worked with ao: Efteling, funda, Flow, Gemeente Amsterdam, Bugaboo


— Casimir Morreau

Casimir is a “complexity pilot”. He knows how to organize people, creativity and energy in such a way that collective intelligence is created: Casimir’s answer to complexity. He brings clarity by designing and facilitating processes and workshops, but especially by inviting people to make a shift. Casimir’s curiosity combined with his commitment to more authenticity makes people want to accept this invitation.

Themes: Innovation, strategy, team culture, creativity, education, branding

Worked with ao: IDEO, Hyperisland, Circle Economy, Tommy Hilfiger, Amsterdam University of Applied Sciences


— Karmen Kekic

As an intuitive and analytical design manager, Karmen leads the way from rough idea to realization. She provides direction by creating clarity. With her personal approach, she manages to create connection, respect and trust: extremely valuable when you want to transform for the better with a group of people. Moreover, Karmen has a keen eye, also for those undercurrents within organizations that are not immediately visible. 

Themes: Change and Innovation management, design management, design direction, design thinking, systems thinking

Worked with ao: NS, Philips Design, University of Twente, Transavia, Studio Dumbar, Clever ° Franke


— Marcel Kampman

Above all, Marcel creates space. By researching the concept with his Happyplaces project and by designing and facilitating. Perceptibly driven by an intense curiosity, he initiates innovation within social, cultural and technological projects. He feels it’s his job, as creative, to clarify complexity, with which things can be made better together. This way, he makes sure all that’s big is accessible to everyone.

Themes: space, innovation, creativity, (editorial) communication, design

Worked with ao: Municipality of Amsterdam, Intershop, Rabobank, Ikea, WeMakeThe.City, Happyplaces Project


—  Martijn Ros

Martijn is the strategist of the Sum Collective. He sees models in everything and knows how to quickly apply structure with this superpower, even when this structure is not obvious. Right there, at that sweet spot, Martijn’s creative mind is able to reveal connections. Provided that the insights are honest, of course. But he can also take care of these. 

Themes: innovation, creativity, strategy, research, futures thinking, design thinking

Worked with ao: Volkswagen, funda, Signify / Philips Lighting, Bugaboo, Randstad


— Martje Kemperman

Everything beautiful starts with attention. Martje has mastered this concept – in a careful and committed way– so she can help people look their monsters in the eye. This creates space to value other perspectives, improve communication and leadership and bring strategy to life. To Martje, everything is change and change is everything: that’s why she is always aware of the latest methods. 

Themes: (personal) leadership, change, strategic internal communication, (executive) coaching, team dynamics, Process Communication Model® (PCM)

Worked with ao: ING, IKEA, PostNL, KPN, ministries and the creative industry (advertising & design).


—  Stef Spijkermans

Simply capturing what unfolds is an art, especially if you also connect with people while doing so. Combined with tying together the nonobvious and voilà: you will get insights à la Stef. Valuable insights, with which the feeling, story, and culture behind brands can come to life, in order to reach people. Because a brand is nothing to Stef, just air: helping people is what matters to him. 

Themes: human research, brand strategy, brand culture, photography

Worked with ao: Fenty, Nike, Protein, Flamingo, This Memento