Coca-Cola's New Coke

In 1985, Coca-Cola had clean data: in blind tests, consumers preferred a sweeter new formula, just as the Pepsi Challenge had been showing. So Coke reformulated, discontinued the original, and launched New Coke in April. The public revolt didn't match the research at all, people weren't upset the new taste was bad, many admitted it was fine. They were furious the original had been taken away. By July, Coca-Cola Classic was back.

For founders and operators, this is a case about what your metrics quietly fail to capture. It sharpens the judgment around any major product or brand change, especially when the data looks unambiguous. The methodological error sitting at the heart of this story is one many teams still make today, and the case is built to make you spot it in your own decisions.