Introduction of a standardized "paternity index" for the statistical evaluation of blood group findings in paternity testing

The introduction of a standardized paternity index (PI) for the statistical evaluation of blood group findings in cases of disputed paternity is proposed and explained. By using the PI $\text{X}\text{Y}$ as parameter, it is not necessary to give the information of the probability of paternity in percent. The PI includes the full information of the blood group findings. In addition to that, by using the suggested standardization based on the probabilities of error according to Schulte Mönting and Walter the test volume is also taken into account. The interpretation of the mathematical result is given by verbal predicates, the limitations of which are orientated by the verbal predicates for the probabilities of error according to Schulte Mönting and Walter, published by us elsewhere. Besides the essential fact that the test volume is taken into account, the most important advantage of this procedure is that the mathematical result is involved in the court decision only by the PI (which is free of any valuation) and its verbal predicate and not by sometimes relatively high percentages, which may be misunderstood by laymen.     

Codification in the Commonwealth: Earlier efforts

This is a revised version of a paper presented at the fourth conference of the Society for the Reform of Criminal Law, Washington, D.C., U.S.A., January 21–25, 1990.