Table 3 |
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Summary output of Bayesian geostatistical models for the north and south of Somalia. |
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|
Model/Variables |
North |
South |
|
|
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|
Bayesian geostatistical model (no covariates) |
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|
α (Intercept) |
-4.62 (-5.44, -4.33) |
-2.9 (-3.37, -2.27) |
|
ϕ (Decay of spatial correlation (degrees latitude and longitude)) |
8.90 (3.11, 12.75) |
4.79 (2.11, 6.97) |
|
σ2 (Variance of spatial process) |
4.35 (271, 7.14) |
7.14 (5.00, 8.76) |
|
DIC |
326 |
1,454 |
|
ME (% PfPR) |
3.83 |
4.14 |
|
MAE (% PfPR) |
4.12 |
5.06 |
|
AU-ROC* |
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|
<5% PfPR |
0.72 (0.64, 0.86) |
0.87 (0.72, 0.91) |
|
5–39% PfPR |
0.66 (0.51, 0.80) |
0.78 (0.66, 0.85) |
|
≥ 40% PfPR |
NA |
0.56 (0.37, 0.73) |
|
Bayesian geostatistical model (with covariates) |
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|
α (Intercept) |
-4.62 (-5.23, -4.10) |
-2.86 (-3.79, 2.27) |
|
ϕ (Decay of spatial correlation) |
10.35 (4.70, 12.88) |
5.78 (2.95, 6.99) |
|
σ2 (Variance of spatial process) |
3.70 (2.17, 7.14) |
5.00 (3.70, 6.70) |
|
DIC |
323 |
1,429 |
|
ME (% PfPR) |
2.56 |
3.65 |
|
MAE (% PfPR) |
4.75 |
5.00 |
|
AU-ROC* |
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|
<5% PfPR |
0.75 (0.64, 0.91) |
0.91 (0.87, 0.99) |
|
5–39% PfPR |
0.64 (0.43, 0.84) |
0.81 (0.70, 0.94) |
|
≥ 40% PfPR |
NA |
0.51 (0.32, 0.83) |
|
Odds ratio, (95% Bayes credible interval) |
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|
Month of survey |
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|
Feb |
Ref |
Ref |
|
Mar |
- |
4.06 (2.20, 7.63) |
|
Jun |
- |
|
|
Jul |
3.25 (0.91, 11.36) |
0.87 (0.48,1.46) |
|
Sep |
0.2 (0.02, 1.74) |
|
|
Nov |
1.31 (0.33, 4.36) |
0.48 (0.23, 0.96) |
|
Dec |
- |
1.95 (0.91, 3.90) |
|
Annual average minimum temperature |
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|
<median of 20.4/22.1 (North/South)°C |
Ref |
- |
|
>median of 20.4/22.1(North/South)°C |
1.12 (0.84, 1.33) |
0.83 (0.67,0.96) |
|
Annual average precipitation |
1.70(0.53, 5.44) |
1.41 (1.07, 1.94) |
|
Distance to water features (km) |
1.22 (0.53, 2.81) |
0.79 (0.74, 1.29) |
|
|
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|
DIC = deviance information criterion (measure of model fit); ME = mean error (measure of overall bias); MAE = mean absolute error (measure of overall precision); AU-ROC = areas under receiver operating characteristic. Values in parentheses are 95% Bayes credible intervals. *There were only two survey locations in the validation set that had PfPR ≥ 40% in the north region meaning reliable AU-ROC values could not be computed for this model. |
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Noor et al. Malaria Journal 2008 7:159 doi:10.1186/1475-2875-7-159 |
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