The whole paradigm changes, though, when you can do daily cancer scans. You don't get a biopsy when the scan shows a lump. You get a biopsy after a couple weeks of daily scans showing the lump growing. Plus, having all the data from the daily scans improves your testing accuracy so false positives and negatives are more rare.

The errors are correlated, not random. Lumps are usually benign cysts. If you start cutting people open for every cyst on a scan, you’d kill a lot more people than you’d save.

This isn’t something you can solve with more scans because the tests test for data that is indistinguishable. They look the same on a scan, there’s an overlap in the assay with some random protein with the same binding sites that is only present in 1% of the population, the coding gene in one person gets repeated in a noncoding region in another, and so on. The “more data” that works is a doctor applying professional judgement (which they’re also famously bad at because biology is a fickle mistress).