Snowball in a Blizzard

There's a running joke among radiologists: finding a tumor in a mammogram is akin to finding a snowball in a blizzard. A bit of medical gallows humor, this simile illustrates the difficulties of finding signals (the snowball) against a background of noise (the blizzard). Doctors are faced with similar difficulties every day when sifting through piles of data from blood tests to X-rays to endless lists of patient symptoms. Diagnoses are often just educated guesses, and prognoses less certain stil