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

Excel threaded comments: The good and the ugly

1 September 2018

Excel 365 is getting a new cell comments system.

This video from Bill Jenen (AKA Mr. Excel) introduces the new system, highlighting the new features and providing advice about how and when to keep the old system.


  • Threaded comments are cool!
  • Old and new comments can co-exist.
  • Why to keep legacy comments.
  • Converting to threaded comments is permanent.
  • How to use legacy comments.
  • New comment VBA.

Update 13 September 2018

The old style of comments, called "Notes", have been restored to the Review ribbon next to the new "Comments" group.

Phantom links

Phantom links

20 August 2018

This article considers the dreaded "phantom link".

That is, Excel displays the security warning "Automatic update of links has been disabled", even though your spreadsheet isn't intended to have any links.

Learn how to easily find and remove phantom links.

Excel Insights

Excel Insights

15 August 2018

Excel Insights is an AI powered service that automatically identifies patterns in your data and provides you with charts you can insert into your workbook.

This article provides an introduction to the features of AI Insights, including the four insight classes:

  • Trends.
  • Rank.
  • Majority.
  • Outliers.
Counting unique values in Excel – 5 effective ways

Counting unique values in Excel – 5 effective ways

13 August 2018

A very common requirement is to count only the unique occurrences of some values. But Excel doesn't have a direct way to count unique values.

In this post we show 5 different ways of counting unique values in Excel:

  • SUM, FREQUENCY and MATCH array formula
  • PivotTable
  • COUNTUNIQUE user defined function
How to use the Data Model in Excel

How to use the Data Model in Excel

2 August 2018

Excel can analyze data from many sources. But are you using the Data Model to make your life easier?

In this post you learn how to create a pivot table using two tables by using the Data Model feature in Excel.

18 best practices for working with data in Google Sheets

18 best practices for working with data in Google Sheets

31 July 2018

This article outlines 18 best practices for working with data in Google Sheets.

Use these practices to make your work more efficient, reduce errors, make your work easier to follow and understand, and add value to the workflow process.

Best practices:

  • Organize your data.
  • Keep a backup copy of your data.
  • Document the steps you take.
  • Go with wide-format data tables.
  • Use good, consistent names.
  • Use data validation for data entry.
  • Even better, use Google Forms for data entry.
  • One cell = one piece of information.
  • Distinguish columns you add.
  • Don't use formatting to convey data.
  • Add an index column for sorting & referencing.
  • Format the header row.
  • Freeze the header row.
  • Turn formulas into static values after use.
  • Keep copies of your formulas.
  • Create named ranges for your datasets.
  • Avoid merged cells.
  • Tell the story of one row.
Step charts in Excel

Step charts in Excel

21 July 2018

Step Charts are useful for showing values that don't change steadily from one point to the next, but that instead are constant for a period of time, then jump to the next level, and are constant for another period of time.

For example, step charts are good for showing how things like postal rates or interest rates change over time.

Step charts are not native to Excel, but it's not hard to build a step chart, with a bit of data tweaking and some smoke-and-mirrors formatting.

There are two ways to build step charts:

  • One geared towards timelines (line charts with X-axis dates) which uses duplicate points.
  • The other towards XY Scatter charts which uses horizontal and vertical error bars.
Formulae referencing current worksheet

Formulae referencing current worksheet

17 July 2018

This article describes problems that can occur when a formula reference includes its own worksheet name.


  • The formula is longer and more difficult to read than necessary.
  • If the formula is copied to another worksheet, then Excel may fail to update references correctly.

To avoid these problems, get into the practice of always removing sheet references to the current worksheet.

[An additional related problem we've seen is that the Sort feature may not work correctly when a formula being sorted includes a reference to its own worksheet name.]

A case study on data quality: Find & clean skunk data with Power Query

A case study on data quality: Find & clean skunk data with Power Query

8 July 2018

This video shows a case study where data quality issues needed to be dealt with before the results could be trusted.

The essence of the message is "...look at our data and investigate the quality of it before we start building models and complex formulas and queries ...".

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