The effect of the uncertainty in the number of contributors to mixed DNA profiles on profile interpretation.

The effect of uncertainty in the number of contributors to a profile is a matter of some contention in forensic DNA interpretation. Interpretation methods are moving towards continuous models. Within this paper the effect of misspecification of the number of contributors to a profile caused by one artefactual peak, either a large back stutter or a forward stutter, was investigated using a continuous model. The misassignment of the number of contributors to a profile either has no significant effect or decreases the LR for the true contributors. It often increases the chance of an adventitious link.