CRIME RATESSelf-Reports. Unlike the UCR and NCVS, self-
report studies refer to a collection of studies con-
ducted by different researchers using a variety of
methodologies. The basic methodology, however,
involves sampling respondents and questioning
them about criminal or delinquent acts. Although
some isolated self-report studies occurred in the
1940s, the technique gained popularity with the
work of Short and Nye (1957, 1958).
Perhaps the most ambitious self-report study
is the National Youth Survey, or NYS (Elliott et al.
1983). This survey involves a national panel sam-
ple. When first instituted in 1976, the panel mem-
bers were aged eleven to seventeen. Estimates of
national-level crime rates for the age groups cov-
ered in this survey can be computed because the
sample of respondents is a national one. These
rates, unlike UCR- and NCVS-based rates, result
from respondents answering questions about their
offenses.
The NYS, and other self-report surveys, calcu-
late two types of crime rates: ‘‘prevalence rates’’
and ‘‘incidence rates.’’ To calculate these crime
rates, the NYS uses the general formula represent-
ed in Equation (1). The prevalence rate uses the
number of respondents who claimed they commit-
ted an offense for the numerator, the number of
respondents for the relevant population size, and
(we choose) 100 for the base. This yields the
percentage of respondents who have committed a
particular act. In the NYS in 1980, when the re-
spondents were fifteen to twenty-one years old,
the prevalence rate for robbery was 2. The inci-
dence rate uses the number of times individuals
claimed they committed a particular act as the
numerator, the number of respondents as the
relevant population size, and typically uses 100,
1000, or 10,000 for the base. We again use 100 for
the base and find that in the 1980 NYS the incident
rate for robbery was 10. Thus, there was an aver-
age of ten robberies per 100 respondents in this
age group in 1980, with only two out of 100
respondents claiming involvement in a robbery.
As with the NCVS, self-report studies depend
upon the accuracy of respondent reports. There-
fore, issues such as telescoping, recall, and embar-
rassment are consequential for self-reports of crimi-
nal activities. In comparison to the UCR and NCVS,
many of the crimes reported in self-report surveys
are trivial crimes or not crimes at all (e.g., lying to
parents or cheating on a test). The sample sizes,
even in the largest of such surveys, are not nearly
as large as sample sizes in the NCVS. Therefore,
given the relative infrequency of serious crimes,
the rates for serious crimes are not very precisely
measured by self-report surveys; that is, the esti-
mates have large standard errors. Nonetheless,
crime rates derived from self-report studies pro-
vide much of the data used to investigate the
determinants of individual criminal offending.SOME PROBLEMS WITH UCR, NCVS, AND
SELF-REPORT DATAUsing information from official data (UCR), vic-
timization surveys (NCVS), and self-report surveys
helps us to gauge the accuracy of crime rates.
Crime rates vary depending upon whether they
derive from UCR, NCVS, or self-report data. To
understand why crime-rate estimates vary depend-
ing upon their source, we briefly outline some
problematic aspects of these three data sources.
UCR Data. The most obvious problem with
UCR data involves underreporting of crimes to
the police. The NCVS interviewers ask respon-
dents whether they reported a particular incident
to the police. In 1994, 78 percent of the respon-
dents who reported a motor vehicle theft to the
interviewer said they reported that crime to the
police, 50 percent of the burglaries were reported,
50 percent of the robberies, and only 32 percent of
rapes and sexual assaults (U.S. Department of
Justice 1997).
Once an incident comes to the attention of the
police a number of factors influence whether the
incident is recorded as a crime or whether an
arrest is made. There may be organizational pres-
sures to raise or lower the crime rate (e.g., Bell
1960; Chambliss 1984; DeFleur 1975; McCleary et
al. 1982; Selke and Pepinsky 1982; Sheley and
Hanlon 1978; Wheeler 1967). The professional
styles of particular police departments may affect
the recorded crime rates (Beattie 1960; Skogan
1976; Wilson 1967, 1978). The interactions be-
tween officers and offenders also help determine
the classification of an incident as a crime and
whether an arrest is made (Black 1970; Smith and
Visher 1981; Visher 1983). Given these and other
problems, it is not surprising that crime rates
recorded by the UCR are known to contain sub-
stantial errors.