guesstimate

Guesstimate is a portmanteau of the words guess and estimate, first used by American statisticians in 1934^[1] or 1935.^[2] It is defined as an estimate made without adequate or complete information,^[3][4] or, more strongly, as an estimate arrived at by guesswork or conjecture.^[2][5][6] Like the word estimate, guesstimate may be used as a verb or a noun (with the same change in pronunciation).

The word is sometimes classified as informal English.^[5] It may be used in a pejorative sense or as an informal synonym for "estimate".^[7][8]

Guesstimation techniques are used:

• in physics, where the use of guesstimation techniques to solve Fermi problems is taught as a useful skill to science students.^[9]
• in cosmology, where the Drake equation is a well-known guesstimation method.^[10]
• in economics, where some economic forecasts and statistics are based on guesstimates.^[11]

Lawrence Weinstein and John Adam's book Guesstimation: Solving the World's Problems on the Back of a Cocktail Napkin, based on the course "Physics on the Back of an Envelope" at Old Dominion University, promotes guesstimation techniques as a useful life skill. It includes many worked examples of guesstimation, including the following problems:

• How many golf balls would it take to circle the Earth at the equator ?

Answer: about one billion (10⁹).^[12]

• How many total miles do all Americans drive in a year ?

Answer: about two trillion (2x10¹²).^[13]

• How much high-level nuclear waste does a 1 GW nuclear power plant produce in a year ?

Answer: about sixty tons.^[14]

See also

• Wiktionary:ballpark estimate

References

Look up guesstimate in Wiktionary, the free dictionary.

1. ^ guess Online Etymological Dictionary
2. ^ ^{a b} guesstimate Dictionary.com Unabridged (v 1.1)
3. ^ guesstimate Merriam-Webster On-line Dictionary
4. ^ guesstimate MSN Encarta Dictionary. Archived 2009-10-31.
5. ^ ^{a b} guesstimate American Heritage Dictionary
6. ^ Compact Oxford English Dictionary guesstimate
7. ^ "Guesstimate with confidence using confidence intervals" from back cover of Statistics for Dummies
8. ^ Guesstimate; Grades 4-6 NTTI Lesson Plan
9. ^ Guesstimation: Solving the World's Problems on the Back of a Cocktail Napkin, Tony Mann, Times Higher Education Supplement
10. ^ The Drake Equation WeAreNotAlone.net
11. ^ Economic outlooks often rely on guesstimation, M. Ray Perryman, San Antonio Business Journal
12. ^ Weinstein & Adam (2008) Problem 3.2
13. ^ Weinstein & Adam (2008) Problem 5.1
14. ^ Weinstein & Adam (2008) Problem 10.5

• Weinstein, Lawrence; Adam, John A. (2008). Guesstimation: Solving the World's Problems on the Back of a Cocktail Napkin. Princeton University Press. ISBN 9780691129495.