# Wald’s Survivorship Airplane Problem

This is a great example where mathematicians applied some creative thinking to solve a very real world problem.  It is Abraham Wald’s Survivorship Bias problem.  To help explain the sequence of concepts that lead to his insight, we made some wooden planes to help visualize the problem, and the solution.

We start out thinking about the planes that come back with artillery damage.  What does that indicate, then we combine all the damage and consider a composite, and finally we consider the planes that don’t come back.  Those are the ones who have the damage we are really interested in.  This is the crux of Wald’s insight.

The activity will be a guided conversation using wooden airplanes to work through the thought process that lead to Wald’s insight on survivorship bias and protecting airplanes in battle.  The full sequence of the conversation is in this lesson plan.

A link to an article from 1984 by Marc Mangel and Francisco Samaniego on Wald’s work on this problem is here.  PNG and Corel versions of this file are in this folder.

It may also be useful to read about other examples of survivorship bias in this wikipedia article.

Presentation Kit Includes:
10 planes with bullet marks
2 planes with no marks
1 plane with composite
Laminated photo of Abraham Wald (or in a frame)  from  Wikipedia
Etched wooden tiles with conversation prompts and history
Copy of summary of Wald’s work (1984),