Inferential Source Attribution from Dust: Review and Analysis.

The analysis of dust allows inference of exposures to geographical areas, environments, activities, and processes. This activity of inferential source attribution is distinguished from that of comparative source attribution, where the focus is on the degree of correspondence between two sources in relation to other possible sources. Review of source attribution efforts in the forensic and broader scientific literature shows that most efforts are limited in one or more of four principal ways, which are classified as: (a) methods based on attribution by direct comparison; (b) methods based on closed-set item classification; (c) analysis using restricted methods and characteristics, and (d) requirement of a large sample size. These limitations provide the context for the requirements of more generalized inferential source attribution. Occurring much more rarely, and almost exclusively in the forensic literature, are individual source attribution case reports that have a microscopical, multidisciplinary perspective. Collectively these are an excellent illustration of potential and their common features demonstrate that (a) a diversity of laboratory expertise and methodology is required in order for source attribution to be successful; (b) different tools need to be applied in different cases, and (c) a process must be in place that allows a facile choice among this diversity of tools, in response to the particular investigative problem and the specifics of the samples that are available. Alternative collaborative mechanisms are considered and recommendations are made for related research and programmatic application.

Reporting of highly individual genetic typing results: a practical approach.

This paper considers the interpretation of serological typing data as a problem in forensic science, as opposed to a problem in population genetics or statistics. Controversies arising in this area are partly due to an overly narrow perspective that ignores basic forensic science principles. After an initial discussion of the special problem that deoxyribonucleic acid (DNA) blood typing poses to forensic science, the three difficulties common to all the proposed interpretive methods are discussed. These are: predicting genotype incidence from allele frequencies, predicting frequencies for the joint occurrence of genotypes in a number of different genetic marker systems, and determining the appropriate population to use to measure the frequencies. The inability to test assumptions that are inherent in our routine methods is noted. This is a procedural weakness that unnecessarily limits the admissibility of DNA typing evidence in court. A practical solution to this problem is offered that begins with minimal assumptions. Initially a statement is made based on (1) how many reference samples the laboratory has typed and (2) how many of these samples show genotypes corresponding to the case samples. The second stage of the presentation begins with a statement that additional assumptions are necessary to fully interpret the evidence and that although these assumptions are scientifically very reasonable, they cannot be absolutely proven. The presentation can then proceed, if desired, to consideration of the specific assumptions and frequency estimates of any of the methods that have been proposed to date. To follow this approach population data must be kept in a form that allows the simple first-stage statement to be made. This means that each individual's record would include typing results in each genetic marker system. Although this method of data storage differs from that used in most forensic science laboratories, it is exceptionally versatile, and allows great flexibility in data analysis.

A medical model for criminalistics education.

The history of medical education during the period of 1870 to 1926 is examined in the context of current issues confronting education in the forensic laboratory sciences. Medical education was radically altered during this period, changing from a rudimentary lecture/apprenticeship system into its modern form. Although the motivating forces had developed over some time, the actual change was quite rapid. By examining how this change occurred, we gain insight into how changes in our own profession might be initiated. Parallels between our current situation and that in medical education 117 years ago include: (1) the primary burden of professional education is borne outside the university in an apprenticeship system, (2) the apprenticeship system is overburdened by a dramatic expansion in the knowledge and skills needed for professional practice, (3) there is no standardized curriculum or accreditation process for educational programs, and (4) there is no educational program that incorporates formal clinical education. Based on this historical analysis, three major goals are proposed: (1) active entreprenurial promotion of professional educational programs by academics, (2) creation of a committee within the American Academy of Forensic Sciences to critique and rate university programs, and (3) the development of a well-defined clinical education program. A model for formalized clinical education in the forensic laboratory sciences is proposed, incorporating clinical professors, student clerkships, and university control over instruction within an operational forensic science laboratory. Benefits from this arrangement include: efficient combination of physical plants, added personnel resources in the laboratory, rapid introduction of research into the laboratory, enhanced prestige for both academics and practitioners, and relief of the laboratory's in-house training burden.