Tim Harford on the tyranny of spreadsheets | Blog | Curio
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Tim Harford on the tyranny of spreadsheets

Jun 30, 2021

When 16,000 potential COVID cases disappeared from Public Health England’s records, the point was raised and the nation was made aware, but it was swiftly buried, never to be spoken about again.

In his long read for the Financial Times, Tim Harford discusses what happens when spreadsheets go wrong. Here’s a little spoiler for you: even Bill Gates didn’t really know what to say except, “It’s good to have people double check things”.

You can listen to the full article here.


Harford begins by showcasing the history of spreadsheets, and while it may not be the most interesting topic, it is incredibly important. He makes a good case (perhaps unwittingly) for hard copy record keeping versus electronic.

After all, the 16,000 cases went missing because Microsoft Excel ran out of numbers. And, as bizarre and hilarious as that might sound, it is the cold, hard truth. 

Harford’s story begins with Francesco di Marco Datini, a merchant from the 14th Century and Luca Pacioli, the so-called Father of Accounting, who wrote the book on the double-entry bookkeeping method in the late 15th Century.

What does this have to do with genetics research? Well, that’s exactly the question Harford goes on to answer. Microsoft Excel was not built for specialist research purposes, it was built for everyday accounting. But, the software was made readily accessible to pretty much anyone who wanted to use it, and because it’s there when specialist software isn’t, scientists have been using it to help them do their jobs -- as they should. 

But maybe… just maybe… they should have some software that’s actually built for them too. 

After all, accountants are trained for their use case, but the rest of us aren’t. In fact, when an investigation was carried out by Felienne Hermans to see how many mistakes were hidden within electronic spreadsheets, she found that if there were any mistakes at all, they only multiplied. This is most likely because Microsoft Excel does it’s best to try and automate the process of doing the work we need it to do, but if the right formulas that flag errors are not put in place, things go unnoticed.

The epidemiologist Bill Foege and his team were among the first to demonstrate the importance of data in tackling diseases, when they were able to catch and trace a case of smallpox in Nigeria in late 1977. As a result, Ali Maow Maalin was the last person to date to have been infected with the disease, because they were able to trace his contacts.

An old file format was to blame for the spreadsheet mishap early on in the COVID-19 pandemic, but it’s thought that 1,500 lives could’ve been lost because of it. This may not seem like many in the wake of the destruction the pandemic has caused, but who wants to tell that to the families of their loved ones?


We can’t change the past, but we can learn from our mistakes. If the pandemic taught us anything when it comes to data, it’s that:

  1. It’s incredibly useful

  2. It saves lives

  3. It needs to be handled and processed with the utmost attention

Happy listening.