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5. When is use of the Qalibra framework appropriate?
As indicated above, the Qalibra framework is intended for assessments requiring quantitative integration of risks and benefits, corresponding to Tiers 3 and 4 in the BRAFO tiered approach (Hoekstra et al. submitted). The need for assessment at Tier 3 is identified by assessment at Tier 2.
The essential difference between Tiers 2 and 3 of the BRAFO approach is that in Tier 2, the balance of beneficial and adverse effects is assessed qualitatively, whereas in Tier 3, it is assessed quantitatively.
Tier 3 is needed when Tier 2 shows that both beneficial and adverse effects are present, but neither is clearly dominant when considered qualitatively. This situation is made more common by the fact that health effects have multiple dimensions, including the incidence of the effect (number of people affected), its severity, its duration, the rate of mortality caused by the effect, and the number of life years lost due to early mortality from the effect. A change in dietary scenario affects these dimensions to differing extents, for different effects, so it will often be difficult to judge the overall adversity or benefit of the health change unless the different dimensions can be integrated in some way. Tier 2 attempts to integrate the dimensions qualitatively, but this can only be done with confidence where either the beneficial or adverse changes clearly dominate. Where this is not possible, approaches that integrate risk and benefit quantitatively are required, such as those provided by the Qalibra framework and in Tiers 3 and 4 of the Brafo approach.