The more detailed we made our plans, the longer our cycle times became.

If you are going to worry about it, I won’t.

If we have drifted 10 heads above the zero line in our coin flip experiment, what is the probability of getting 10 tails in a row to return us to zero? About 1 in 1,000.

Reducing risk, which is the primary mission of testing, clearly creates economic value for product developers. In fact, reducing risk is so centrally important to product development that it is indispensable for us to quantify its economic impact.

To manage product development effectively, we must recognize that valuable new information is constantly arriving throughout the development cycle. Rather than remaining frozen in time, locked to our original plan, we must learn to make good economic choices using this emerging information.

In product development, our greatest waste is not unproductive engineers, but work products sitting idle in process queues.

Since high capacity utilization simultaneously raises efficiency and increases delay cost, we need to look at the combined impact of these two factors. We can only do so if we express both factors in the same unit of measure, life-cycle profits. If we do this, we will always conclude that operating a product development process near full utilization is an economic disaster.

In our factories, we create flexibility by paying more to workers who can work at more stations on a production line. We value flexibility, and we pay for it. In contrast, most product development organizations exclusively reward specialization.

We should not prioritize on the basis of project profitability, but rather on how this profitability is affected by delay.

The more detailed we made our plans, the longer our cycle times became