Products are developed with groups of people. These groups of people need to have a common idea what the product they are developing should look like at the end. Product development is considered a social process where the end result is created in negotiation between all participants. Literature show that having more shared understanding about the intended end result of the project leads to more successful products. Shared understanding is a common interpretation, or framing. When the interpretations about a product of two people overlap, the product has many similar relationships with other pieces of information within the minds of both persons. But the pieces of information one has in his mind and the way these pieces are placed in his mental networks, are influenced by previous experiences, education, culture, etc. This implies that when people are working together, they will have different perceptions of the task, the context and the outcome because their pasts will not be completely similar. And this mismatch in perceptions can lead to problems in collaboration. Consider the situation where a person thinks it is good enough if a consumer can use a microwave after reading the manual. If he cooperated with someone who wants to create a self-explaining product, they will not understand each other when discussing the way the end user needs to setup the microwave. A strong factor in determining the content and the links in the mental networks of individuals is the organizational culture. This claim is supported by literature and empirical evidence in this report. Organizational culture comprises of for instance the following elements: jargon, products, stories, behavior, values, mission and habits. Some of these elements are nested very deep in an organization and so taken for granted that they are not questioned anymore. Because they are so deeply integrated in the organization and taken for granted, it is hard for organizational members to be aware of the presence and to express them when asked. These elements are called assumptions. At Océ, people from different R&D sites work together to create new products. Sometimes people from other organizations are involved in the product development too, think of employees of Flextronics, Benchmark, Konica Minolta and Canon. Each Océ R&D site has its own distinct organizational culture, since the history, jargon, stories and habits differ. And the variance with the organizational culture from Océ Technologies in Venlo with that of the external companies is even bigger as less is hold in common. The divergence in organizational culture hinders the creation of shared understanding in product development teams. Unfortunately, creating better or more specifications is not the answer to the difference in interpretations throughout the project team. The creator of the specifications founds the specs on assumptions. And the same assumptions might not exist at the other organization where they work with this list of requirements. The receiver of the requirements misses then some essential building blocks to come to the same interpretation of the requirement as the creator did, leaving room for new and different interpretations. Only in discussion can the receiver create a similar interpretation of the requirements as the sender. An attempt was made in this graduation project to define what kind of organizational assumptions are used in product development. In the study, it became clear that a full list of organizational assumptions cannot be created in a half year time, because the context determines what assumptions are used and in what way. The same reason made the creation of a communication tool useless, as the context in the next project or over an half year would be so different, the communication tool would not fit anymore. Something that would certainly lead to improvement is to raise awareness of the role organizational assumptions can play in New Product Development. When people have this awareness, they will start communicating more careful, leaving room to discuss the assumptions in their work. And a game appeared the best form to gain awareness of the role of organizational assumptions in New Product Development. The developed game is called ‘Princen: Assumptions in product development’. In ‘Princen’, that can be played by 6 people at the same time, the participants mimic the creation of a convectional microwave in a co-creation setting with 6 different companies. In the game, the participants read a rich story about a company that will influences them. Next, the participants select images to express what their company wants to achieve in the convectional microwave project. Participant will make decisions. In the game, the group has to decide which developments to carry out. ‘Will we do A or B?’ These developments have an effect on the character of the convectional microwave. After a game, a reflection takes place, In the reflections, the facilitator will ask questions that leads the participant to: 1) Awareness that a part of his mental knowledge network relies on organizational culture. 2) Awareness of the differences that exists in this specific part of his mental knowledge network with people working for other organizations, which results in problems. 3) Discover at least 2 example from the participants’ own work where organizational assumptions influenced the decisions. The game was tested with Océ employees as participants and it was possible to meet the three named objectives. The participants also indicated the game to be fun and a good learning experience. It is expected that the game could be a relevant training within Océ R&D to enhance the cooperation between R&D sites and outside organizations. This is done by creating awareness that product development is a social process where assumptions influence the interpretation and several of these assumptions come from the organizational identity. With this awareness, the product development will benefit because it will reduce the development time, minimize errors and the outcome will be better products.