Customers in each segment expect different levels of reliability. Reliability is expressed as Mean Time Between Failure, or MTBF. MTBF predicts the number of hours a product will work before it fails.

MTBF is changed on the R&D screen. Products can be manufactured with MTBFs above or below the range that customers expect. Customers are indifferent to products with MTBFs above the range, but for every 1,000 hours below the range, demand drops by 20%. At 5,000 hours below the range demand drops to 0.

As products become smaller, faster and more reliable, their material costs increase making them more expensive to produce so it's a challenge for R&D to design products that conform to customer demand, while controlling material cost.