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

Combine data from multiple worksheets into a single worksheet

1 July 2018

This tutorial shows you the exact steps required to combine multiple sheets into one single table using Power Query.

When using Power Query to combine data from all the Tables in a workbook, you will likely face an issue where Excel double counts your data. The tutorial also shows you how to avoid this issue.

A sample workbook is available to download, so you can follow each of the steps yourself.

Importing and cleaning data with Power Query

Importing and cleaning data with Power Query

24 June 2018

If you work with any type of data, then you know that rarely does it come perfectly in the format you need. Power Query (also called Get & Transform in Excel 2016) is the solution to this problem.

Power Query is an amazing ETL tool (Extract, Transform, and Load). If you're not using it then you're missing out on the best new feature in Excel.

This article shows you, via an example, how to import and clean complex and messy data using Power Query.

How to use SUMPRODUCT with multiple criteria

How to use SUMPRODUCT with multiple criteria

17 June 2018

There are situations where several criteria are required to add up the right numbers. That's straightforward if the numbers are found in a single column using SUMIF. Yet when you find your data in several columns, more complex formulas are needed.

This article shows you how to use SUMPRODUCT with multiple criteria to add numbers from multiple columns.

Financial modeller's 10 worst nightmare

Financial modeller's 10 worst nightmare

12 June 2018

A list of the top 10 worst nightmares for a financial modeller, and how to solve them:

  • Cleaning up someone else's models.
  • Circular references appearing where you did not expect them.
  • The financial model crashes, and you don't have a backup.
  • Worksheet compatibility issues.
  • A balance sheet that does not balance.
  • Changes in accounting standards or applicable fiscal regimes which, in turn, make your life miserable.
  • The first time you are asked to build a cash-flow waterfall when the only waterfall you knew was Niagara Falls.
  • Clients who have Excel phobia.
  • When you are given a financial model in Portuguese and your level of Portuguese is limited to the lyrics of Amar Pelos Dois from Salvador Sobral.
  • Being called a data cruncher.
Problem with two AutoSum

Problem with two AutoSum columns

8 May 2018

This article explores a pitfall of using Excel's AutoSum feature.

When not used according to Excel's arcane set of rules, everything may appear okay but you can easily introduce an error where some values are omitted from the AutoSum.

A workaround is also suggested, to ensure that AutoSum continues working as expected.

Create a running balance in Excel that allows you to insert, delete, and move rows

Create a running balance in Excel that allows you to insert, delete, and move rows

26 April 2018

Calculating a running balance is a common and important spreadsheet task.

But inserting rows, deleting rows, and moving rows via cut and paste can introduce hard-to-detect errors in a running balance formula.

This article explains the problems with the basic running balance formula and provides two robust solutions.

Excel’s AVERAGE function – the hidden pitfalls

Excel’s AVERAGE function – the hidden pitfalls

17 April 2018

AVERAGE is one of those easy functions in Excel. Like, super easy! It has just one argument, the cells, or numbers to be averaged.

So what's the problem? It's too easy to get wrong, yet we might not notice for weeks, months, years or ever.

There are many ways to calculate an average. Different formulas will fit with different datasets and scenarios. The critical thing is to know your data and exactly what you want to achieve.

Preview of Stocks and Geography, new data types in Excel

Preview of Stocks and Geography, new data types in Excel

14 April 2018

For more than 30 years, Excel's data types have been very basic: text, numbers, Booleans, and dates. The user had to assign meaning to the data, which often leads to errors.

But that is starting to change. Microsoft has introduced the concept of linked data types into Excel. The first two linked data types are Geography and Stocks.

This article describes the new data types, with examples of how to use them.

The new data types are being rolled out to Office 365 users this month.

Also see Excel help: Stock quotes and geographic data.

Excel hidden data warning

Excel hidden data warning

8 April 2018

Have you seen the articles that blame Excel for all kinds of business errors?

In some cases, problems occur because rows were hidden, and that distorted the data analysis.

To help avoid those problems, I created a sample file that shows an Excel hidden data warning, if rows or columns are hidden.

Remember, as the old saying goes, it's better to be safe, than to read about your catastrophic errors on the internet.

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