Table 4 Confidence limits (95%) for PPV and NPV values for simulations presented in Fig. 6. Prevalence threshold 30% two years after cessation of MDA. Data from 300 village simulations with 500 people per village

Test positive

0

242

242

Test negative

36

22

58

Totals

36

264

300

95% Confidence limits

Estimated value

Lower limit

Upper limit

Prevalence of interruption

0.880

0.836

0.913

Sensitivity

0.917

0.875

0.946

Specificity

1

0.880

1

Probability of simulation being either transmission interruption or bounce back

 Interruption

0.807

0.756

0.848

 Bounce back

0.193

0.151

0.243

For predicted elimination - probability of being true or false

 True positive (PPV)

1

0.982

1

 False positive

0

0

0.019

For predicted bounce back - probability of true or false

 True negative (NPV)

0.621

0.483

0.741

 False negative

0.379

0.258

0.516

Likelihood ratios

 Positive (C)

Infinity

–

Infinity

 Negative (C)

0.083

0.056

0.124

 Positive (W)

Infinity

–

Infinity

 Negative (W)

0.611

0.431

0.867