Table 3.
Exploration of the predicted probability, sensitivity, specificity, AuROC, PPV and NPV of selected individual and combined DAP items
| Description | Predicted probability of pregnancy at DAP score | Empirical cut-point | Sensitivity | Specificity | AuROC | PPV | NPV | Domains covered | Positive and negatively worded items | |
| 0 | 4 | |||||||||
| Total DAP: All 14 items |
79.4% | 0.9% | 1.96 | 78.0% | 81.0% | 0.85 | 43.0% | 95.0% | All | Yes |
| Single DAP item: Pregnant: good thing for me. |
66.7% | 2.1% | 2.5 | 68.1% | 86.3% | 0.77 | 49.0% | 93.3% | 1 | Positive only |
| Single DAP item: Baby: end of the world for me. |
27.4% | – | 0.5 | 65.3% | 77.7% | 0.72 | 36.2% | 92.0% | 1 | Negative only |
| Two DAP items: Pregnant: good thing for me and Baby: end of the world for me. |
71% | 0.7% | 1.25 | 65.3% | 90.1% | 0.78 | 56.0% | 93.1% | 1 | Yes |
| Three DAP items: Pregnant: good thing for me, Pregnant: excited, Baby: hard to achieve other things. | 83% | 2.8% | 2.15 | 62.5% | 87.1% | 0.75 | 48.4% | 92.3% | All | Yes |
| Three DAP items: Pregnant: good thing for me, Pregnant: excited, Baby: end of the world for me. | 73% | 1.2% | 1.49 | 66.7% | 87.4% | 0.77 | 50.5% | 93.1% | 1, 2 | Yes |
| Three DAP items: Pregnant: good thing for me, Baby: end of the world for me, Baby: makes me smile. | 68% | 1.0% | 1.49 | 69.4% | 84.4% | 0.77 | 46.3% | 93.5% | 1, 2 | Yes |
| Three DAP items: Pregnant: good thing for me, Baby: want, Baby: end of the world for me. | 72% | 13.9% | 1.49 | 66.7% | 90.3% | 0.79 | 57.1% | 93.3% | 1 | Yes |
| Three DAP items: Pregnant: good thing for me, Baby: end of the world for me, Baby: hard for me to manage. | 76% | 8.8% | 1.82 | 75.0% | 77.2% | 0.76 | 38.8% | 94.1% | 1, 3 | Yes |
| Four DAP items: Pregnant: good thing for me, Pregnant: excited, Baby: want, Baby: end of the world for me. |
73% | 1.4% | 1.63 | 66.7% | 89.2% | 0.78 | 54.5% | 93.2% | 1, 2 | Yes |
| Four DAP items: Pregnant: good thing for me, Pregnant: excited, Baby: end of the world for me, Baby: hard to achieve other things. |
81% | 1.2% | 1.88 | 66.7% | 83.9% | 0.75 | 44.4% | 92.9% | All | Yes |
| Six DAP items: Pregnant: wouldn't mind, Pregnant: unhappy, Baby: want, Baby: positive addition to life, Baby: makes me smile, Baby: hard for me to manage. |
73% | 1.6% | 1.93 | 75.0% | 80.9% | 0.78 | 43.2% | 94.4% | All | Yes |
AUROC, area under the receiver operating curve; DAP, Desire to Avoid Pregnancy; NPV, negative predictive value; PPV, positive predictive value.