Modelling (pre-)Design Activities With a Multi-Stakeholder Perspective - Principia Designae: Pre-Design, Design, and Post-Design - page 169

further needs is sometimes induced by new products and it is sufficient to generate
an innovation process and to determine the success of a novel product. For example,
Velcro or Post-it are typical outcomes of serendipity, but they are also the result of
innovators' skill of creatively meeting the observation of reality with tacit customer
needs. Conversely, Apple products are the fruit of technology-driven processes in
which innovation has relied on the talent of anticipating the emerging needs
induced by new technical products.
Despite the growing interest on needs (either explicit or tacit) as a compass for
the development of innovative products, traditionally a design activity starts from a
design specification to fulfil, which is related to, but not coincident with the needs
intended to satisfy. In detail, the design specification is a “structured and formalised
information about a product” (Ericson et al. 2009 ) consisting of a set of require-
ments, each entailing “a metric and a value”. A proper design specification is
therefore constituted by a list of measurable features such that it is possible to
assess whether the needs are satisfied in a given context and constitute the reference
for the development of a not-yet-designed product.
An accurate analysis of the differences between needs and requirements appears
in (Ericson et al. 2009 ), where Ericson et al. distinguish between the customer's
context, where values and needs are perceived by the users, and a second context,
which is the product developers' context, where requirements and specifications are
designed by the development team. The bridge is represented by the “Need Rep-
resentation” stage in which needs are generated and designed by the heterogeneous
development team on the basis of what has been found in the customer's context.
During this process the information captured from the customer's context should be
converted by the designer into information usable for the product development.
Nevertheless, in the engineering design literature, a clear distinction between
methods that address Needs Identification or Requirements Definition does not
exist, presumably because of an unclear distinction between the two concepts.
Indeed, it is only possible to recognise an orientation towards one of the two targets.
Beyond the debate on needs overviewed in the previous subsection, the literature on
requirements specification has become much larger since the 1990s following the
development of complementary approaches including Quality Function Deploy-
ment (e.g., (Clausing 1998 ) ) and detailed prescriptive criteria to codify the infor-
mation gathered from external sources (e.g., (Cooper et al. 1998 )). A
comprehensive survey about methods for mapping design requirements has been
presented in Darlington and Culley ( 2002 ) .

12.3 Building on the Situated FBS Model

Many models have been proposed in literature to represent the design process; some
of them are prescriptive in nature, i.e., they aim at guiding design tasks; others are
essentially descriptive, thus they represent designers' behaviour and thinking