This article intends to contribute to the ongoing debate about forensic DNA databases, by considering European legislative dispositions that regulate these databases and analysing the person-stain match ratio in relation with the size of the database in European countries.
However, Santos et al. have published that the comparison of person-stain match figures in the context evaluated in their article would indicate that the expansion of a forensic DNA database does not necessarily mean obtaining greater performance in terms of person-stain matches (Santos et al., 2013).
Nevertheless, the results determined by Q-PCR and IHC staining match one another in the grade and stage of diseases as described below.
In the case of stain-matches, all I have to do is multiply together a bunch of probabilities in order to get an answer.
The legislative configurations of the expansive countries appear to indicate the option increase the number of included individuals in the DNA database in order to enhance the number of person-stain matches.
By comparing the performance ratio with the proportion of the population included (Figure 1) the data show that a DNA database's performance in terms of person-stain matches is not linked to its size in terms of individuals included.
In other words, a high "performance ratio" of person-stain matches per person indicates that the "right" people are being included in the database (ENFSI 2012), meaning that the included individuals are the ones that present a good chance of matching crime scene stains.
The success of a considerable number of person-stain matches in the first operational years of databases can be compared to the initial success of the exchange of information between some members of the Prüm Treaty when many unidentified crime scene stains were identified, allowing cross-border crimes to be solved (McCartney et al. 2011).
This aim of this article is not to provide a different method to measure or assess the impact of DNA databases, but rather to analyse European countries' legislative criteria for inclusion and retention of profiles and then to consider the effects in terms of the association between the number of individuals included and the number of person-stain matches.
Hence, the contents of Table 3 were adapted from a report produced by the European Network of Forensic Science Institutes (ENFSI) DNA Working Group (ENFSI 2012) and include a "performance ratio" ("person-stain matches per person" in the original) calculated from the most recent available data which dates from December 2011 (ENFSI 2011).
Available data do not support the idea according to which the size or the proportion of the total population that is included in a forensic DNA database is linked to its output in terms of measured person-stain matches (Figure 1). Figure 1 Scatter plot of the performance ratio and proportion of population from expansive and restrictive countries.
