Figure 4

Differences between the lung cancer mortality risk and prediction variance computed by the Bayesian and geostatistical methods. Maps (A, B) highlight the counties where the Bayesian and geostatistical methods differ the most in terms of risk estimates (absolute differences) and prediction variance (relative differences). A diverging color scheme with three breaks (mid-point = 0 or 1) was chosen; counties with values in between the breaks receive a blend of the two break colors. (C) ATA Poisson kriging yields larger risk estimates than BYM model in high-valued areas, while lower risks are predicted in low-valued areas. (D, E) The lognormal hypothesis underlying the BYM model leads to larger prediction variance for larger risk estimates, once the effect of the population at risk is accounted for through the division by the kriging variance. In all scatterplots, the size of the dots is proportional to the population at risk.