Fermi Estimation
Back of the envelope estimation is an important skill - one that Manhattan Project physicist Enrico Fermi was fascinated by. Fermi estimation isn’t just a case of guessing, you can use a structured approach to estimating numbers, and you’re often able to get to your estimation using multiple logic paths as a check.
Example applications
Fermi estimation is a useful technique when we don’t have much data about a problem. The classic Fermi estimation might include
Steps
- take what you know about a problem, and work in the order of magnitude
- make simple assumptions and justifications
- in our case, verify your estimation using data that you can access
Key concepts
When preparing your resource, you should consider covering:
- the situations when Fermi estimation might be useful, and an example
- the process for generating a rapid order-of-magnitude estimation
- alternative ways of triangulating or verifying your Fermi estimation
- advice for student engineers about considerations of the likely error in a Fermi estimation, such as over- or under-estimation
Core resources
Similar concepts…
Fermi estimation is a “back-of-the-envelope” or “rapid estimation” technique. There are many others that might be suitable.