The IAA quickly identified that the potsherd itself was an authentic potsherd, which led to the assumption that the inscription on it was also authentic. However, there are thousands of potsherds similar to the unauthenticated ostracon lying around Lachish.For more on confirmation bias, see here.Avni said the experts fell into a mistake common not just in archaeology, but in all types of science: they already believed the item was real, and they performed tests that confirmed that bias.
Background on the story, with my commentary, is here and links.
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