I was lucky to date a girl who was into math, and who was coding those "machine learning" algorithms for a radiology startup here in Shenzhen.<p>She had a lot of scepticism for what she did. One of biggest showstoppers she said was the unpredictability of errors.<p>An algo can catch 99% tumors, including tiny ones, bur can randomly pass over very obvious ones which a human radiologist will spot with his eyes closed.<p>They had a demo day with radiologists, and them throwing tricky edge case xrays at the computer. Edge cases were all ok, but one radiologist pulled his own xray from his bag, with a 100% obvious, terminal stage tumor, and to company's embarrassment, the algo failed to detect it no mater how they twisted and scaled the xray. The guy then just walked out.