OK, I looked at the actual paper, and what 94% actually is is the 0.94 area under the curve for the receiver-operating characteristic curve (the plot of the true positive rate (TPR) against the false positive rate (FPR) at each threshold setting) not the accuracy for a specific binary result (e.g. at a specific arbitrary threshold).

See https://www.sciencedirect.com/science/article/pii/S155608641...

> In general, an AUC of 0.5 suggests no discrimination (i.e., ability to diagnose patients with and without the disease or condition based on the test), 0.7 to 0.8 is considered acceptable, 0.8 to 0.9 is considered excellent, and more than 0.9 is considered outstanding

So .94 is actually extremely good.