Nominal weights as a function of the prevalence ratio and prevalence <i>π₀</i>.

Abstract

<p>Nominal weights are shown for 5 fixed prevalence ratios: 10, 5, 2, 1, and 0.5, which are in ascending order in the figure. The x-axis is the denominator prevalence <i>π₀</i>. Nominal weights increase rapidly as the numerator prevalence <i>π₁</i> approaches 1; as the numerator class becomes more like a “perfect sentinel”.</p