We’re developing requirements for our product, including setting reliability requirements. Or we’re setting acceptance criteria for our test plans.
What confidence levels do we choose? We don’t have to blindly set them - we can base it off the risks of failure, using our FMEA (failure mode effects analysis).
We should choose a confidence level for our requirements or their test plans. We can associate that confidence level with the level of risk associated with our product.
If we have an FMEA, we can find the place in the table where our requirement is a control or where it's associated with a potential failure mode and cause. When we find it, then we have a lot of metrics we can use to help us decide on a level of confidence to test based on risk. And if we've done our FMEA earlier, then we would've had it populated with information from our cross-functional team in a time of cool heads, without the pressures of project management. It will be an objective input into what confidence level we should require for our test.
FMEA is a great tool for us to refer to, to help us choose a relevant confidence level by basing our decision on one or more metrics that the FMEA can provide.