Depending on how much attention you've paid to the evolution of AI this may come as a surprise, or seem expected. Without data, what's an algorithm to do?

Note: this couldn't be a better argument for standardized and universally-accessible electronic health records. Watson isn't perfect, but it can't parse what isn't there, or is there, but only partially, and not transcribed from decades of horrific handwriting, and not in any sort of standardized format.