Body mass index (BMI) is a common method used to assess body weight relative to height. The reason it is so commonly employed is because it is a simple, indirect measure of body composition because it correlates highly with body fat in most people, however, the inherent flaws in the method limit the accuracy of the assessment. The weight excess or deficiency may, in part, be accounted for by body fat, although other factors such as muscularity also affect BMI significantly (see below). In studies by the National Center for Health Statistics,