Table 2. Accuracy of the estimated prevalences of obesity from height and weight values reported by parents.
| 1st grade | 1st grade | 4st grade | 4st grade | |
| male | female | male | female | |
| n=83 | n=87 | n=99 | n=107 | |
| True positive (n) | 10 | 14 | 16 | 13 |
| False positive (n) | 1 | 1 | 3 | 1 |
| False negative (n) | 2 | 1 | 2 | 2 |
| True negative (n) | 70 | 71 | 78 | 91 |
| Sensitivity (%) | 83.3 | 93.3 | 88.9 | 86.7 |
| Specificity (%) | 98.6 | 98.6 | 96.3 | 98.9 |
| False positive rate (%) | 1.4 | 1.4 | 3.7 | 1.1 |
| False negative rate (%) | 16.7 | 6.7 | 11.1 | 13.3 |
| Predictive value positive (%) | 90.9 | 93.3 | 84.2 | 92.9 |
| Predictive value negative (%) | 97.2 | 98.6 | 97.5 | 97.8 |
| Estimated prevalence (%) (Pe) | 13.3 | 17.2 | 19.2 | 13.1 |
| Actual prevalence (%) (Pa) | 14.5 | 17.2 | 18.2 | 14.0 |
| Difference (%) ( Pe-Pa ) | -1.2 | 0.0 | 1.0 | -0.9 |
Pe: the estimated prevalence of obesity as calculated by body mass index (BMI) from reported height and weight values, Pa: the actual prevalence of obesity as calculated by BMI from actual height and weight values.