Effect of proportion of double negative cases on percent bias. Effect of the proportion of double negative cases on percent bias in observed sensitivity (A) and specificity (B). Note that the scale of the y-axis of the specificity graph (B) is enlarged to show minute changes. Parameter definitions are as in "Parameters" (Table 6), except that the proportion double negative cases is allowed to vary. Otherwise as Figure 3.
Ringham et al. BMC Medical Research Methodology 2010 10:3 doi:10.1186/1471-2288-10-3