Because these apportionment results were to be applied in time-series analyses, another evaluation of the consistency of the source apportionments across research groups and apportionment methods was conducted.
Finally, we evaluated the size and significance of the additional variability introduced to the PM mortality, time-series analysis by variations in the source apportionment process across groups and methods, consistent with the primary goal of this workshop.
It is clear from the comparisons that the variability introduced by the uncertainty of the across-source apportionment groups and analyses is small, relative to the overall uncertainty of these estimates.
The patterns evidence the feature of loss aversion described by prospect theory [7], [12], the allocation or apportionment of preference across goal-objects described by the Matching Law [40], [76], and the limits/behavioral adaptation described by alliesthesia [43], [45].
After all the estimated source-specific impact assessments were submitted by workshop participants, the agreement across source apportionment analyses was evaluated.
The apportionment of variance was consistent across a wide range of percentile thresholds and using a variety of normalization methods.
These various daily PM2.5 mass source apportionments were then independently submitted before the workshop (in April 2003), and each was individually evaluated for their respective associations with daily mortality in each city in a consistent manner across the various apportionment research groups/methods.
Again, this consistent mortality analysis approach across source apportionments allowed a direct comparison of the daily mortality effect estimates across the various source apportionment analyses in each city.
Keeping the health effects model consistent across the various source apportionment researchers and methods allowed a separate discernment of the extent to which variability in the source apportionment step contributed to variability in the ultimate health effects analyses results.
Based on the relative sizes of these intergroup intercorrelations for each of the source types in these two cities, the soil-, sulfate-, residual oil-, and salt-associated mass components were generally seen to be most unambiguously identified by the various source apportionment methods, while vegetative burning and traffic were less well correlated across groups.
