numeracy

It is challenging to explain probabilities that go beyond the difference between the words, probabilities, and odds. [1] In fact, when we use words to describe numbers, it often increases the ambiguity of their meaning – something is lost between sender and receiver in the translation.
For all the regulation of what's written in direct-to-consumer health ads (and for all the hand-wringing about informed consent), there's little said about what patients understand. As it turns out, health literacy is a problem. And those with the biggest problems are looking for help in all the wrong places.