Is Making Assumptions Similar to Making Mistakes

Is Making Assumptions Similar to Making Mistakes

Over the past week, I received a couple of interesting questions. One concerned assuming a Weibull beta value for an accelerated life test plan. The second involved assuming expected life models for elements within a reliability block diagram.

In both cases, we faced incomplete data and uncertainties, yet felt the need to assume some values in order for the math to work out. We do make assumptions in order to solve problems. We also can make mistakes that lead to unwanted consequences.

For example, if a mechanical engineer is designing a load-bearing beam and assumes the material strength is larger than it is in reality, the beam will collapse. In this simple example, the assumption was the mistake.

Sometimes, the assumptions we make are fine and sometimes they mislead us and may lead to mistakes. So, how can we know when an assumption is reasonable or when it will lead to problems?

Why and when do we make assumptions?

As engineers, we are tasked with solving problems. Given the complexity of even a simple component, we use assumptions to simplify the problem allowing solutions. Our tools and understanding allow us to avoid overly…