Cargo cult science comprises practices that have the semblance of being scientific, but do not in fact follow the scientific method. The term was first used by physicist Richard Feynman during his 1974 commencement address at the California Institute of Technology.
Cargo cults are religious practices that have appeared in many traditional tribal societies in the wake of interaction with technologically advanced cultures. They focus on obtaining the material wealth (the "cargo") of the advanced culture through magical means, by building landing strips, mock aircraft, mock radios, and the like.
The speech is widely posted and Feynman adapted it in his book Surely You're Joking, Mr. Feynman!. Feynman based the phrase on a concept in anthropology, the cargo cult, which describes how some pre-scientific cultures interpreted technologically sophisticated visitors as religious or supernatural figures who brought boons of cargo. Later, in an effort to call for a second visit the natives would develop and engage in complex religious rituals, mirroring the previously observed behavior of the visitors manipulating their machines but without understanding the true nature of those tasks. Just as cargo cultists create mock airports that fail to produce airplanes, cargo cult scientists conduct flawed research that superficially resembles the scientific method, but which fails to produce scientifically useful results.
The following is an excerpt from a speech (taken from the book).
In the South Seas there is a cargo cult of people. During the war they saw airplanes land with lots of good materials, and they want the same thing to happen now. So they've arranged to imitate things like runways, to put fires along the sides of the runways, to make a wooden hut for a man to sit in, with two wooden pieces on his head like headphones and bars of bamboo sticking out like antennas—he's the controller—and they wait for the airplanes to land. They're doing everything right. The form is perfect. It looks exactly the way it looked before. But it doesn't work. No airplanes land. So I call these things cargo cult science, because they follow all the apparent precepts and forms of scientific investigation, but they're missing something essential, because the planes don't land.