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Figure 9 | Environmental Health

Figure 9

From: Bias magnification in ecologic studies: a methodological investigation

Figure 9

Bias magnification and inflation. The ecologic bias (b e - b w ) equals the individual-level bias (b c - b w ) – due to confounding by group and effect modification of the risk difference by group – multiplied by the magnification factor M, assuming no other sources of ecologic bias. The ecologic bias also equals the sum of the individual-level bias due to ignoring groups and the bias caused by aggregation. The latter is measured by F, the inflation factor, equal to M - 1.

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