Table 1.
Example | True RR and exposure-outcome counts, without misclassification | Levels of outcome misclassification | Observed RR and exposure-outcome counts, with misclassification | Observed outcome PPVs and consequence of misclassification | ||||
---|---|---|---|---|---|---|---|---|
1a | True RR: 0.86 (95% CI, 0.75-0.98) |
|
Observed RR: 0.87 (95% CI, 0.76-0.99) |
|
||||
With outcome | Without outcome | |||||||
With outcome | Without outcome | Exposed | 219 | 9781 | ||||
Unexposed | 10 085 | 389 915 | ||||||
Exposed | 215 | 9785 | ||||||
Unexposed | 10 000 | 390 000 | ||||||
1b | True RR: 0.70 (95% CI, 0.60-0.81) |
|
Observed RR: 0.87 (95% CI, 0.76-0.99) |
|
||||
With outcome | Without outcome | |||||||
With outcome | Without outcome | |||||||
Exposed | 175 | 9825 | ||||||
Exposed | 210 | 9790 | ||||||
Unexposed | 10 000 | 390 000 | ||||||
Unexposed | 9702 | 390 298 | ||||||
1c | True RR: 1.00 (95% CI, 0.88-1.13) |
|
Observed RR: 0.87 (95% CI, 0.76-0.99) |
|
||||
With outcome | Without outcome | With outcome | Without outcome | |||||
Exposed | 223 | 9777 | ||||||
Exposed | 250 | 9750 | ||||||
Unexposed | 10 241 | 389 759 | ||||||
Unexposed | 10 000 | 390 000 |
The data are from a hypothetical cohort study of 10 000 exposed individuals, 400 000 unexposed individuals, and a baseline outcome prevalence of 2.5%.
CI, confidence interval; PPV0: outcome positive predictive value among unexposed; PPV1: outcome positive predictive value among exposed; RR: relative risk; SN0: sensitivity among unexposed; SN1: sensitivity among exposed; SP1: specificity among exposed; SP0: specificity among unexposed; PPV: overall outcome positive predictive value;.