In short, ordinary fingerprints and DNA profiles have opposite economic characteristics. Ordinary fingerprint databanks have low variable costs and high fixed costs, and DNA typing databanks have high variable costs and comparatively low fixed costs. Those considerations imply that different decisions could be appropriate as to whether, when, and how to develop each kind of databank. For example, because of the high variable cost per sample, considerable thought must given to whose DNA profiles should be stored. To maximize the "return per sample," one should concentrate on persons convicted of crimes with documented high rates of recidivism, such as rape, as discussed below.

Cost analysis is made more difficult by the rapidity of change in DNA typing technology. For example, PCR-based methods might greatly reduce DNA typing costs: blood samples might be replaced with simple buccal swabs (i.e., cheek scraping); Southern blots might be replaced with non-gelbased formats; complicated scoring of the problematic continuous allele system used in RFLP analysis might be replaced with discrete mechanical allele scoring. Accordingly, today's cost assessments must be viewed as tentative.

WHOSE SAMPLES SHOULD BE INCLUDED?

In deciding whom to include in a DNA profile databank, it is necessary to consider the likely forensic utility of the data and the protection of individual privacy. It is helpful to consider six categories of people.

Samples from Convicted Offenders

DNA profile databanks containing profiles of criminal offenders must be justified on the basis of the likelihood of recidivism. The Bureau of Justice Statistics7 found that, of the 108,580 persons released from prisons in 11 states in 1983, an estimated 63% were rearrested for a felony or serious misdemeanor within 3 years, 47% were reconvicted, and 41% returned to prison or jail (Table 5-1). They were charged with a total of 326,746 new offenses in the 3-year period; more than 50,000 charges were related to violent offenses, including approximately 2,000 homicides, 1,500 kidnappings, 1,300 rapes, 2,600 other sexual assaults, 17,000 robberies, and 22,600 other assaults. Of the prisoners who had been incarcerated for violent offenses, 60% were rearrested within 3 years for similar offenses. Recidivism rates were highest in the first year. Four of every 10 released prisoners were rearrested in the first year; nearly one-fourth were convicted of new crimes; and nearly one-fifth were returned to prison or sent to jail. Most rearrests occurred in the states in which the prisoners were released, although about 15% occurred in other states. Of course, high recidivism



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