Your Reliability Engineering Professional Development Site
The analysis of parts and components to predict the rate at which an item fails. In parts count prediction, the expected or known failure rates for all components within an item are tallied to estimate the item’s overall failure rate. (However, this method is proven to be very inaccurate at estimating the actual field failure rate.)
All models are wrong, some are useful. ~ George E. P. Box
If you know me, you know I do not like MTBF. Trying to predict MTBF, which I consider a worthless metric, is folly.
So, why the article on predicting MTBF?
Predicting MTBF or creating an estimate is often requested by your customer or organization. You are being specifically asked for MTBF for a new product.
You have to come up with something.
Just a short post to point to a paper on the accuracy of part count prediction techniques. A few years ago, I recalled seeing a paper that studied the difference between various parts count methods and actual results.
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If only we had a crystal ball or another device to predict the future. From the general wondering about the enemies next move, to the soldier hoping their equipment will work. In the corporate boardroom estimating the competitions next move, to the maintenance manager ordering spare parts, we have many uses for knowing the future.
We often look to past performance to provide an indication of the future. Has this mutual fund regularly provided adequate returns? If so, we predict it will going forward. And anyone that has reviewed mutual fund performance also has read or heard the admonishment to not use past performance to estimate future returns. Mutual funds, markets, business and battlefields all change and respond in sometimes unforeseen ways. [Read more…]