Observed response rate
|
True response rate**
|
Bias (observed-true)/true (%)
|
---|
30%
|
30%
|
< 1%
|
40%
|
36%
|
10%
|
50%
|
43%
|
16%
|
60%
|
49%
|
21%
|
- *From Table 4, where the positive predictive value (PPV) was 76% and the negative predictive value (NPV) was 90%. **Computed as True rate = Observed rate × (PPV + NPV-1)-NPV + 1 [39]. Numbers are rounded to the nearest whole integer but the actual values were used to calculate the bias.