Figure 1

Sensitivity and completeness formulas. a. Sensitivity of a diagnostic test is calculated as follows: A/(A + C). Cell D represents healthy animals correctly classified as test-negative. b. Completeness of the disease information in each of four national cattle databases (CoDDs) was calculated as a/(a + c). The Table covers cases of disease (not animals). Cell d represents cases of clinical mastitis not recorded by participating farmers or in the CoDD.