Equations for Goal Setting
Abstract
Chris and Fred discuss what equations (if any) exist for setting and optimizing reliability goals … sometimes trading off against other goals. Wo …
Key Points
Join Chris and Fred as they discuss equations that exist to help you come up with and optimize reliability goals and targets. This comes from a listener who points out that well-known reliability software contains equations based on Weibull distributions, optimization algorithms, and perhaps alchemy that can do all this for you. What do we think?
Topics include:
- Reliability doesn’t always cost more. This is important. Many producers that successfully implement a quality and reliability improvement initiative tend to magically spend less money on product development, and take less time to do it. That’s right, you can improve reliability, reduce costs, and speed up time to market all at the same time. How? Quality and reliability initiatives tend to eliminate crises and issues during production that otherwise cost time and money. Hewlett-Packard famously did this during the 1980s, reducing warranty returns by a factor of eight, while reducing production costs and time to market. Remember this …
- Reliability optimization frameworks tend to assume reliabiltity costs more. Which isn’t always true (as above). You will often see university level equation frameworks where models that link increased reliability with increased costs … pretty much always. Which immediately invalidates them.
- And then there is market share … While it is generally true that things like market share are dependent on reliability, this relationship can sometimes be weak. While customers will tend to buy more reliable products at similar products, they need to find out about it. If two products offer a 2-year warranty period, then the customer is not provided any other information on reliabiltiy to help them prefer one over the other. If one of these products is more reliable than the other, the same warranty period effectively hides this.
- And then there is the dodgy mathematics and statistics. The example in quesiton used the Weibull distribution to model market share. Without justification.
- The takeaway? Just because a website or a textbook as an equation that alledgedly optimize reliabiltiy goals with retail costs and everything else … doesn’t mean it is valid. Not even a little bit. If there are equations, ask why they are valid. The Weibull distribution is great at modelling fatigue failure mechanisms. But market share??? Come on …
Enjoy an episode of Speaking of Reliability. Where you can join friends as they discuss reliability topics. Join us as we discuss topics ranging from design for reliability techniques to field data analysis approaches.
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