Table 1.
Results of Bayesian geostatistical models to predict prevalence of P. vivax and P. falciparum for Tanna Island, 2008.
| Coefficient, posterior mean | Odds ratio, posterior mean (95% Bayes credible intervals#) | DIC | |
|---|---|---|---|
| Model of P. vivax with distance to coastline fixed effect | |||
| α (intercept) | -4.680 (-5.317- -4.137) | ||
| Distance from coastline (OR per 1 km) | -0.690 (-1.151- -0.242) | 0.730 (0.591-0.895) | |
| Φ (rate of decay of spatial correlation)* | 251.5(51.26-569.4) | ||
| σ2 (variance of geostatistical random effect)** | 0.214 (0.056 - 0.624) | ||
| DIC | 306.9 | ||
| Model of P. vivax with elevation fixed effect | |||
| α (intercept) | -4.611 (-5.327 - -3.931) | ||
| Elevation (OR per 100 m) | -0.547 (-0.992- 0.115) | 0.654 (0.468, 0.917) | |
| Φ (rate of decay of spatial correlation)* | 167.8 (33.71, 461.2) | ||
| σ2 (variance of geostatistical random effect)** | 2.471 (1.271, 4.304) | ||
| DIC | 308.9 | ||
| Model of P. falciparum with distance to coastline fixed effect | |||
| α | -5.238 (-6.027 - -4.625) | ||
| Distance from coastline (OR per 1 km) | -0.101 (-0.534 - 0.334) | 0.955 (0.783, 1.165) | |
| Φ | 289.5 (51.61 - 575.4) | ||
| σ2 | 0.584 (0.057 - 4.713) | ||
| DIC | 219.5 | ||
| Model of P. falciparum with elevation fixed effect | |||
| α | -5.129 (-5.976 - -4.416) | ||
| Elevation (OR per 100 m) | -0.207 (-0.673 - 0.146) | 0.864 (0.603, 1.149) | |
| Φ | 238.2 (53.28 - 478.9) | ||
| σ2 | 1.753 (0.4521 - 4.079) | ||
| DIC | 218.9 | ||
* The unit is change in spatial autocorrelation per decimal degree. A lower Φ indicates that spatial correlation occurs over longer distances (i.e. spatial clusters are larger).
** A higher variance indicates a greater tendency toward spatial clustering.
# Bayes credible intervals can be interpreted as having a similar meaning to confidence intervals used in frequentist statistics.