Never assume a spreadsheet is right, even your own.
Raffensperger (2001)
Spreadsheets contain errors at an alarmingly high rate.
Abraham, et al (2005)
Programmers exhibit unwarranted confidence in the correctness of their spreadsheets.
Krishna, et al (2001)
Spreadsheets are notoriously error-prone.
Cunha, et al (2011)
Research on spreadsheet errors is substantial, compelling, and unanimous.
Panko (2015)
Even obvious, elementary errors in very simple, clearly documented spreadsheets are... difficult to find.
Galletta, et al (1993)
Spreadsheet development must embrace extensive testing in order to be taken seriously as a profession.
Bock (2016)
Errors in spreadsheets... result in incorrect decisions being made and significant losses incurred.
Beaman, et al (2005)
People tend to believe their spreadsheets are more accurate than they really are.
Caulkins, Morrison, & Weidemann (2006)
Despite being staggeringly error prone, spreadsheets are a highly flexible programming environment.
Abreu, et al (2015)
Spreadsheets are dangerous to their authors and others.
Durusau & Hunting (2015)
Spreadsheets are easy to use and very hard to check.
Chen & Chan (2000)
Overconfidence is one of the most substantial causes of spreadsheet errors.
Sakal, et al (2015)
The quality and reliability of spreadsheets is known to be poor.
Bishop & McDaid (2007)
Errors in spreadsheets are as ubiquitous as spreadsheets themselves.
Colbenz (2005)
Spreadsheets are the most popular live programming environments, but they are also notoriously fault-prone.
Hermans & van der Storm (2015)
Most executives do not really check or verify the accuracy or validity of [their] spreadsheets...
Teo & Tan (1999)
Spreadsheets are extraordinarily and unacceptably prone to error.
Dunn (2010)
It is now widely accepted that errors in spreadsheets are both common and potentially dangerous.
Nixon & O'Hara (2010)
Spreadsheet errors have resulted in huge financial losses.
Abraham & Erwig (2007)
Spreadsheet errors are pervasive, stubborn, ubiquitous and complex.
Irons (2003)
...few incidents of spreadsheet errors are made public and these are usually not revealed by choice.
Kruck & Sheetz (2001)
Every study that has looked for errors has found them... in considerable abundance.
Panko & Halverson (1996)
Your spreadsheets may be disasters in the making.
Caulkins, Morrison, & Weidemann (2006)
A lot of decisions are being made on the basis of some bad numbers.
Ross (1996)
The software that end users are creating... is riddled with errors.
Burnett & Myers (2014)
Spreadsheets are commonly used and commonly flawed.
Caulkins, Morrison, & Weidemann (2008)
Most large spreadsheets have dozens or even hundreds of errors.
Panko & Ordway (2005)
60% of large companies feel 'Spreadsheet Hell' describes their reliance on spreadsheets.
Murphy (2007)
Spreadsheets are more fault-prone than other software.
Kulesz & Ostberg (2013)
Spreadsheet shortcomings can significantly hamper an organization's business operation.
Reschenhofer & Matthes (2015)
1% of all formulas in operational spreadsheets are in error.
Powell, Baker, & Lawson (2009)
Spreadsheets are often hard, if not impossible, to understand.
Mireault & Gresham (2015)
Spreadsheets have a notoriously high number of faults.
Rust, et al (2006)
Spreadsheets... pose a greater threat to your business than almost anything you can imagine.
Howard (2005)
Studies have shown that there is a high incidence of errors in spreadsheets.
Csernoch & Biro (2013)
A significant proportion of spreadsheets have severe quality problems.
Ayalew (2007)
Developing an error-free spreadsheet has been a problem since the beginning of end-user computing.
Mireault (2015)
The results given by spreadsheets are often just wrong.
Sajaniemi (1998)
Spreadsheet errors... a great, often unrecognised, risk to corporate decision making & financial integrity.
Chadwick (2002)
94% of the 88 spreadsheets audited in 7 studies have contained errors.
Panko (2008)
The issue is not whether there is an error but how many errors there are and how serious they are.
Panko (2007)
Spreadsheets can be viewed as a highly flexible programming environment for end users.
Abreu, et al (2015)
The untested spreadsheet is as dangerous and untrustworthy as an untested program.
Price (2006)
Spreadsheets are alarmingly error-prone to write.
Paine (2001)
It is irrational to expect large error-free spreadsheets.
Panko (2013)
Despite overwhelming and unanimous evidence... companies have continued to ignore spreadsheet error risks.
Panko (2014)
Every study, without exception, has found error rates much higher than organizations would wish to tolerate.
Panko (1999)
Spreadsheet errors are still the rule rather than the exception.
Nixon & O'Hara (2010)
Untested spreadsheets are riddled with errors.
Miller (2005)

Spreadsheet bibliography

Title Are we overconfident in our understanding of overconfidence?
Authors Raymond R. Panko
Year 2014
Type Proceedings
Publication First Workshop on Software Engineering Methods in Spreadsheets
Series July
Abstract

In spreadsheet error research, there is a Grand Paradox. Although many studies have looked at spreadsheet errors, and have found, without exception, has error rates that are unacceptable in organizations, organizations continue to ignore spreadsheet risks.

They do not see the need to apply software engineering disciplines long seen to be necessary in software development, in which error types and rates are similar to those in spreadsheet development.

Traditionally, this Great Paradox had been attributed to overconfidence. This paper introduces other possible approaches for understanding the Grand Paradox. It focuses on risk blindness, which is our unawareness of errors when they occur.

Full version Available
Sample
Bat and ball

You are told that a bat and ball cost a dollar and ten cents and that the bat costs a dollar more than the ball.

How much does the ball cost?

A typical response is that the ball costs ten cents. This is wrong, of course.

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