Decent Pretty Good. A little bit buggy- for instance, it won't let me type decimals into any of the text boxes. Also, I have to use "prevalence" instead of pre-test probability, which is not the terminology I learned. It would also be nice to be able to put the LR's in directly. Still, all in all, it's not a bad app, and it's the only one of its kind that's free, so it's what we're stuck with.