The systems used in the UK have been subjected to a number of academic studies. These have typically shown that E-FIT and PRO-fit produce composites that are correctly named, either immediately or a few hours after construction, about 20% of the time (see Brace et al. (2000), Bruce et al. (2002), Davies et al. (2000) and Frowd et al. (2005)). When witnesses in these studies are required to wait two days before constructing a composite, which matches real use more closely, naming falls to a few percent at best (e.g. Frowd et al. and [2007). The reason for the low level of naming from these systems appears to be that witnesses are unable to accurately construct the internal features of the face after long delays, the region that is important for recognition by another person later (Frowd et al. ).