Landscaping Firm's Trusted Spreadsheet Had a Hidden Error for Over a Year

A small landscaping company had relied on a manually built monthly spreadsheet for years to track crew profitability, but consultants discovered a formula error that had gone undetected for roughly a year. A subcontractor cost was excluded from the crew-profit calculation, making every crew appear slightly more profitable than it actually was. The mistake stemmed from an inherited spreadsheet originally built by a bookkeeper who had since left, leaving the current office manager unfamiliar with parts of its logic. The cumulative error was significant enough that the business owner had already made a strategic decision — about which type of work to pursue — based on the flawed figures. The case highlighted a broader tension between automating data collection and preserving the human judgment needed to catch such discrepancies during manual review.