Difficulties in calculating MTBF and reliability

Mean Time Between Failure (MTBF) is an important metric for determining the lifetime of embedded system components, but it’s difficult to calculate with accurate results. These difficulties lead to unreliable figures, which has generated backlash against such calculations.

One typically defines reliability as the probability that said device will perform functionally as required for a specified period of time. This all seems rather simplistic, and it can be, to a degree, with a large enough sample size and a long enough period of time. The main issue with deriving such figures is that they are required for a product’s release – not at the end of its lifetime when actual reliability can be determined.

Full report published here in Embedded Computing Design – April 2014