FIGURE D-2 The effect of correlation between usual intake and requirement on the prevalence of inadequate intakes estimated using the Estimated Average Requirement (EAR) cut-point method for 10 values of the correlation. For all correlations, mean intake = 90, standard deviation (SD) of intake = 30, EAR = 55, and SD of requirement = 15 units.

NOTE: When the SD of requirement increases relative to the SD of intake, increasing the correlation between intake and requirements can result in noticeable bias of the EAR cut-point method even when the correlation is as low as 0.4.