Uncertainty in reliability estimation: When do you know everything you know?

In this paper we demonstrate the use of an adapted Grounded Theory approach through interviews and their analysis to determine explicit uncertainty (known unknowns) for reliability estimation in the early phases of product development. We have applied the adapted Grounded Theory approach in a case study in the medical systems industry. In this paper it will be shown that a large number of factors affecting reliability and its uncertainty can be identified, and that exhaustiveness regarding the number of these factors can be achieved using an adapted Grounded Theory approach. Moreover, these factors can be related to the various stages in the product lifecycle. Thirdly, taking a holistic approach, we conclude that these factors can be physical (product related) as well as non-physical (process related) in nature. Finally, we discuss the possibility to extend this research towards a quantified approach using Bayesian Networks.