["Advantages" of exclusion probability in blood group evaluation?]

There is no apparent advantage in using exclusion probability A (or WA) in cases where parentage is disputed in either normal or special cases. Furthermore, WA provides no more information than WEM. However, the converse is true: WA does not take the serotype of the putative father into account. Moreover, it is neither easier to understand nor easier to work with and, like WEM, it also requires a prior probability. WA is also not helpful in interpreting WEM; for this, one has to use mean WEM values for fathers and non-fathers. There is no reason to expect WA and WEM to converge at the upper end of the scale. WA is unsuitable for establishing the borderline where decisions may no longer be valid, as the error quota in individual cases can be greater than that allowed within the limits. 100-WEM % is the probability or error in categorical decisions in 100 cases with similar combinations. In contrast, 100-WA % cannot provide a reliable probability of error in individual cases because WA does not take full account of the phenotype of the putative father.