Overprecision

Overprecision occurs when an overly specific conclusion is drawn from the evidence.

The argument is fallacious for much the same reasons as an argument from omniscience. Because the arguer does not have the knowledge necessary to justify their argument, it is not valid. (In this case, of course, the arguer does not claim unlimited knowledge — merely knowledge that is outside of what they know.)

The fallacy occurs most often in advertising campaigns, Internet arguments, or viral hoaxes. This works as a successful bullshitting method because it implies that the value cited is precise to the number of significant figures quoted, e.g., 7.5% implies a precision between 7.45% and 7.55% — thus giving the impression that some real science went into the number. The more numbers after the decimal point that there are, the more likely you can assume where they pulled it from.

The fallacy is an informal fallacy and similar to the argument from omniscience.

Alternate names

 * Fake/False/Misplaced precision
 * Spurious accuracy/rigor

Examples

 * The trigonometry calculation came out to 5,005.6833 feet, so that's how wide the cloud is up there.
 * The museum guide says the dinosaur skeleton is 90,000,006 years old — because when he was hired six years ago he was told that it was 90 million years old.
 * The time for the Olympic 30-kilometer relay race, which takes almost an hour and a half to run, is measured to one one-hundredth of a second.

Darrell Huff, in How to Lie With Statistics, relates the following story: