Although it was devised around 1840, the body mass index (BMI) didn’t become the favored measure of fatness until the early 1970s, when it started to appear in health studies exploring at the influence of a person’s weight on health and fitness. Now, after 40 years in the limelight, BMI has a competing measure. Its creators, a father and son team of doctor and engineer, call it “A Body Shape Index,” or ABSI. The Los Angeles Times reports that rather than measure weight divided by height (as does BMI), the ABSI takes waist circumference (in centimeters) and divides that by the product of two variables. The first is the square root of your height (in centimeters); the second is the square of the cube-root of your BMI. Yes, it’s complicated, but don’t worry; if it catches on, there will soon be an app to do the math. Why should you care? ABSI inventors claim that when they calculated the ABSI of more than 14,000 people, they found it to be a more accurate measure than both waist circumference and BMI in predicting death. Read more about it in the L.A. Times.