Right now, if a doctor wants to measure or record someone's pain, she'll generally just ask her patient about it, or ask her patient to rate his pain from 1 to 10. That will always be a very important part of diagnosis, Wager says, but having a less subjective measure could nevertheless help. Some people, such as very young, very old or certain disabled people, can't communicate well. Others may underreport their pain—or are less likely to be believed.