In 1950, researchers in the Air Force measured 4063 pilots on 140 different physical dimensions, ranging from things like their weight to things like the distance between their eyes and their ears.%%note:The End of Average by L. Todd Rose © 2016%% The goal was to update the average pilot size, which was used to design and build cockpits and hadn't been remeasured since 1926.
However, when Lieutenant Gilbert S. Daniels compared the new average with the individual pilot records, he discovered something startling: not a single one of the four-thousand-plus pilots was within 15% of the average on the ten most relevant dimensions (things like height and chest circumference). In fact, for any given three dimensions, fewer than 4% of the pilots would qualify as average. There simply was no such thing as an "average" pilot, and therefore cockpits designed for the average fit nobody.
Daniels' discovery led to the creation of adjustable seats and straps like those we find in cars and helmets today, along with a corresponding increase in pilot comfort and performance. It's a useful shorthand for the idea that "one size fits all" strategies are rarely as effective as flexible or modular strategies.