I watched Rob Eastaway's 2019 for the Royal Institute today. Everything from RI is great and worth checking out, but Eastaway delivered a statistic I hadn't come across before: 90% of all spreadsheets contain errors. Mr Eastaway himself had only come across the statistic from another source, the European Spreadsheet Risks Interest Group (or EuSpRIG for short). This is not a trivial issue. EuSpRIG's website has a "horror stories" section that demonstrates the gravity of errors in the wrong type of spreadsheet. Even if we discard the few stories involving malware embedded in spreadsheets like the BlackEnergy power plant shutdown - for many reasons it makes sense to count and study malware separately from unintentional human and formulaic errors - the EuSpRIG lists dozens of separate incidents that involve massive financial losses . Taxes, criminal and medical records are all stored on spreadsheets. Single digit error rates have major repercussions. Claims put...