Design Flaws and Quality-Related Feedback in Product Development
Author: Gries, Bruno
Supervisor: Blessing, L. & Adreasen, M. M.
Institution: Technische Universität Berlin
The subject of this thesis are design flaws, how different stakeholders in the affected products react to them and how design flaws may be corrected. It deals with the question of how to improve the quality of products by taking into account the expressed or implied need for a change in their design. As a number of product examples show, this need is not always considered or understood by companies. These examples also illustrate that design flaws not only have a technological, but also a legal and an economic dimension. Based on the perception that design flaws are a specific form of quality defect, existing concepts of quality and its management are reviewed. Yet, current research in this field proves to be an insufficient theoretical basis for interpreting, correcting and ultimately learning from design flaws. Therefore, a generic model of design-related product quality is proposed which describes the interaction between designers, product attributes and the various stakeholders in a product. Based on this model, product quality is defined as the degree to which perceived product attributes match with expected attributes. Accordingly, a design flaw is defined as a design- related product attribute that impairs product quality. An important aspect of the abovementioned model is feedback. It is shown that feedback is an important element of design and product development processes and that there are various potential sources from which companies might obtain quality-related feedback about their products after they have entered the market. However, existing studies give little detail on key questions related to design flaws. A fundamental notion of this thesis is that a design flaw is the result of a design failure, i.e. the failure to achieve a sufficient level of product quality. Therefore, the conditions under which this kind of failure can occur are investigated, identifying four major failure modes: 1) misinterpreting the expectations of stakeholders, 2) poorly communicating product-related information to stakeholders, 3) not understanding the product as the stakeholders would and 4) failing to implement the product attributes as intended. To complement the theoretical findings of this thesis, an exploratory study of 171 German companies was undertaken. It reveals deficiencies in post-project communication between manufacturing and design departments and identifies cases in which products were brought on the market despite the fact that their design flaws were known. It also shows that innovating implies successfully correcting design flaws, the latter being a challenge that companies need to face as a whole.