Prove by Test vs. Prove by Design

So you want to develop a new product or service. You thoroughly research the market expectations and they become your requirements (i.e. the specification). You plan your approach, do design work, build samples and run tests to check the results. Maybe the first results weren't so good so you make modifications and the new results show the product meets the specification requirements. You run additional tests to confirm - they're positive. You're elated you achieved success, right? After all, your test results prove the product is capable.

Although a bit oversimplified, the above paragraph describes the product development process generally used in the US and Europe. Will a Japanese customer accept the product as developed? Absolutely not! Why?

The fact that 10, 100, or even 1000 tests were successful does not guarantee the 11th, 101st, or 1001st sample will also be good. Japanese engineers have been conditioned to seek to understand the details, the process that caused a part to be good. Test results themselves do not prove the product design is robust. A detailed explanation of what caused the product to function properly is expected.

Along with an explanation of why the part functions, an analysis of the potential failure points and how the design was carefully thought through to avoid them is required. Only then will the Japanese engineer agree the design is robust, and will view the test results as an indication the design itself is robust. In other words - prove by design.

The concept of Prove by Test vs. Prove by Design is one of the most significant differences in the Japanese and Western product development processes. Learn the method of Prove by Design and you'll see your product performance increase while at the same time significantly reduce warranty and quality issues.