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An Excel Covid-19 Debacle

Updated: Apr 20, 2023

In October 2020, the incompetent use of an outdated version of Excel resulted in nearly 16,000 unreported Covid-19 positive cases in England, raising questions about data management practices and the accuracy of NHS Covid data.

What went wrong?

The errors first came to light when a member of the public uncovered a discrepancy between two of the spreadsheets used by the NHS.

It was quickly established that the spreadsheet had incorrectly entered data into two cells, causing discrepancies in the total number of cases reported.

As the test numbers increased, larger volumes were uploaded and at some point the data exceeded Excel’s 65,536 row limit, meaning thousands of test results were not transferred.

Public Health England was using an old version of Excel, with a limit of 65,536 rows of data.

Excel Debacle

The NHS has since conducted a thorough investigation into the cause of the error, and has identified a number of procedural and technical issues that led to the mistake.

The NHS has implemented a number of changes to ensure that similar errors do not occur in the future, including improved training for staff and more rigorous quality control procedures.

Excel Debacle

Impact of the errors on data accuracy

The errors had a significant impact on the accuracy of the data reported by the NHS. and have raised questions about the reliability of all reported data.

The errors also caused confusion among the public, as the incorrect figure was widely reported in the media. This led to a lack of trust in the data, and a decrease in confidence in the NHS.

Furthermore, the errors caused a delay in the release of the data, as the NHS had to take the time to correct the errors.

Lessons learned for future data handling

The errors in the Excel spreadsheet have highlighted the importance of careful data handling. All data should be checked and double-checked to ensure it is accurate and up-to-date. Employees should also be aware of their responsibilities when it comes to data entry, and any errors should be reported as soon as possible.

In addition, it is important to ensure that data is stored securely and that access is restricted to those who need it. Regular backups should be taken to ensure that data is not lost in the event of a system failure.

Implications for NHS Covid response

The errors in the Excel spreadsheet could have had serious implications for the NHS Covid response. If the incorrect figures had been allowed to remain, it could have caused confusion or led to an inaccurate picture of the current situation. As such, it is important that errors are identified and corrected as soon as possible.

The NHS has been under immense pressure during the Covid-19 pandemic, and any errors in the data could have had a significant impact on the response. It is essential that data is accurate and up-to-date in order to ensure that the NHS can respond effectively to the pandemic. Furthermore, it is important that data is regularly checked and updated to ensure that it remains accurate and reliable.

Potential for other errors in NHS Covid data

The errors in the Excel spreadsheet may be just the tip of the iceberg. Given the complexity of Covid-19 data and how quickly it changes, there is a potential for further errors to go unnoticed. It is essential that regular checks are carried out to ensure that all data is accurate and up-to-date.

In addition, it is important to ensure that data is collected and stored in a consistent manner. This reduces the risk of errors and ensure that the data is reliable and trustworthy. Furthermore, it is important to have a system in place to quickly identify and rectify any errors that may occur.

Microsoft’s spreadsheet software is one of the world’s most popular business tools, but it is regularly implicated in errors which can be costly, or even dangerous, because of the ease with which it can be used in situations it was not designed for.

Excel Debacle

The latest version of Excel at the time of writing, has a maximum 1,043,576 rows and 16,384 columns.

Excel’s Inherent Risks

In 2013, an Excel error at JPMorgan masked the loss of almost $US6bn (AUD$8.88bn), after a cell mistakenly divided by the sum of two interest rates, rather than the average.

Professor of law at the University of Connecticut, James Kwak, warned:

There is no way to trace where your data comes from, there’s no audit trail (so you can overtype numbers and not know it), and there’s no easy way to test spreadsheets, (and that's) just for starters.

"The biggest problem is that anyone can create Excel spreadsheets – badly.

"Because it’s so easy to use, the creation of even important spreadsheets is not restricted to people who understand programming and do it in a methodical, well-documented way,”


Philip Seigel CPA FFIN, 13 May 2021

Comdex Training Centre


See all our Excel related articles here

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