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

Spreadsheet bibliography

Title The cognitive science of spreadsheet errors: Why thinking is bad
Authors Raymond R. Panko
Year 2013
Type Proceedings
Publication 46th Hawaii International Conference on System Sciences
Series January, pages 4013-4022
Abstract

Research has long shown that spreadsheet developers are 96% to 99% accurate when they enter information into spreadsheet cells. For large spreadsheets, unfortunately, a cell error rate of 1% to 6% [sic] will almost certainly lead to incorrect results.

Can cell error rates (CERs) really be this high? General human error research has shown that when humans do simple but nontrivial cognitive tasks, they inevitably have comparable error rates. The problem is that human cognitive mechanisms have evolved to "gamble" in a way that will be correct nearly all of the time but that will fail a few percent of the time. Furthermore, our brain hides its inaccuracy from us, leaving us to believe strongly in the correctness of our work despite the presence of errors.

This paper looks at cognitive science aspects of spreadsheet error commission. A subsequent paper will look at spreadsheet error detection.

Full version Available
Sample
Probability of spreadsheet error
Probability of spreadsheet error
The probability of an error for different cell error rates and calculation steps quickly approaches 100%. Even for a low cell error rate and a moderate number of cells, a spreadsheet is almost certain to contain at least one error.
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