FIGURE 2.

A: Hypothetical plot of individuals’ observed measure compared with individuals’ known personal requirements or BNS concentration for a nutrient. The line at the 45° angle reflects the point at which an observed value is equivalent to an individual's personal need. Persons above the 45° line (shaded area) are inadequate for a nutrient; persons below the 45° line are adequate for a nutrient. B: Illustration of mathematical equivalence between the number of persons below an average reference value and the number of persons who experienced inadequacy. The vertical line reflects the point at which an observed value is equivalent to a reference value (ie, 1200 units). The line at the 45° angle reflects the point at which an observed value is equivalent to an individual's personal need. Triangles 1 and 2 (diagonal hash lines) are bounded by the vertical line and the 45° line. The number of persons in triangle 2, which can be determined by readily available data, is equal to the number of persons in triangle 1, which is unknown. The numerical count for the gray shaded area to the left of the vertical line is known; the numerical count for triangle 2 (known) can be substituted for the count for triangle 1 in the gray shaded area. Modified from reference 2 and reproduced with permission from National Academies Press.