A discussion of current issues and concepts in the practice of skull-photo/craniofacial superimposition

A recent review paper on cranio-facial superimposition (CFS) stated that "there have been specific conceptual variances" from the original methods used in the practice of skull-photo superimposition, leading to poor results as far as accuracy is concerned. It was argued that the deviations in the practice of the technique have resulted in the reduced accuracies (for both failure to include and failure to exclude) that are noted in several recent studies. This paper aims to present the results from recent research to highlight the advancement of skull-photo/cranio-facial superimposition, and to discuss some of the issues raised regarding deviations from original techniques. The evolving methodology of CFS is clarified in context with the advancement of technology, forensic science and specifically within the field of forensic anthropology. Developments in the skull-photo/cranio-facial superimposition techniques have largely focused on testing reliability and accuracy objectively. Techniques now being employed by forensic anthropologists must conform to rigorous scientific testing and methodologies. Skull-photo/cranio-facial superimposition is constantly undergoing accuracy and repeatability testing which is in line with the principles of the scientific method and additionally allows for advancement in the field. Much of the research has indicated that CFS is useful in exclusion which is consistent with the concept of Popperian falsifiability - a hypothesis and experimental design which is falsifiable. As the hypothesis is disproved or falsified, another evolves to replace it and explain the new observations. Current and future studies employing different methods to test the accuracy and reliability of skull-photo/cranio-facial superimposition will enable researchers to establish the contribution the technique can have for identification purposes.