Impact of missing attributes on the novelty metric of Shah et al

The a posteriori novelty metric proposed in 2003 by Shah and colleagues is still one of the most widely used in design research, constituting the reference for many experiments on creativity and effectiveness of ideation. However, recent research highlights that in the presence of ideas implementing different numbers of attributes, some non-negligible problems arise. The objective of this paper is to estimate the potential errors that can be committed when applying the metric of Shah et al. in these situations. The investigation has been performed by relying on a high number of randomly generated virtual sets of ideas. The results obtained revealed that the problem of “missing attributes”, if not opportunely faced, leads the considered metric to misleading novelty scores.