Table 2

Zero inflated Poisson models for landmine victim counts in the two years before the 2000–2001 surveys in Chad and Thailand, as functions of community level variables

Community level explanatory variables in each model componentBest Chad Model*Best Chad Model fit to Thai dataBest Thai ModelBest Thai Model fit to Chad data
*“Best” refers to final model in a backwards stepwise variable selection process using the Chad data; the next set of columns results from analysis of the same variables with the Thailand data. The last two sets of columns reverse the roles of the two countries’ data. †Exponentiated coefficients yield rate ratios in the Poisson component, odds ratios in the binomial logistic component. ‡95% Confidence intervals for the exponentiated coefficient. §The entries for this variable are only coincidentally equal to those for the Best Thai Model; they differ in the fourth significant digits.
Poisson component for rate in increased risk group Exp(b)† 95% CI‡ Exp(b) 95% CI Exp(b) 95% CI Exp(b) 95% CI
Log10(Population)1.250.99 to 1.581.531.02 to 2.291.420.94 to 2.141.331.04 to 1.71
Mine/UXO emplacement in previous two years1.871.33 to 2.641.350.90 to 2.04
Pasture blockage by mines/UXO1.421.07 to 1.901.481.04 to 2.10
Water source blockage by mines/UXO1.371.05 to 1.801.371.01 to 1.86
Unexploded ordnance reported2.050.88 to 4.760.610.44 to 0.85
Logistic component for odds of being in increased risk group
Log10(Population)3.871.62 to 9.252.32§1.00 to 5.362.321.00 to 5.361.760.91 to 3.43
Log10(Distance (km) to nearest community with victims)0.250.13 to 0.510.240.14 to 0.400.290.17 to 0.480.190.10, 0.36
Mine/UXO emplacement in previous two years14.61.14 to 1884.281.78 to 10.32.971.32, 6.706.721.07 to 42.2
Pasture blockage by mines/UXO7.442.91 to 19.01.630.91 to 2.90
Water source blockage by mines/UXO0.260.07 to 0.921.390.77 to 2.521.881.06 to 3.350.630.25 to 1.58
Road blockage by mines/UXO7.282.21 to 24.01.300.35 to 4.88
Anti-personnel mines reported9.041.93 to 42.31.320.50 to 3.54
Unexploded ordnance reported31.43.72 to 2652.481.29 to 4.78
Anti-tank mines reported2.721.52 to 4.853.071.46 to 6.45