Measures of Crime: A Pressing Issue for the Future of Criminology

“Measurement is the basis of all science” [1, p. 70]. Regardless of the subject matter, whether in physics or chemistry, psychology or criminology, every scientific discovery has a measurement process attached. A process that can be more or less complex, depending on the accuracy intended and, of course, the complexity of the object in question. In the particular case of criminology, where crime is the fundamental object of study, researchers struggle with a variable that is inherently difficult to measure.

Regardless, researchers from multiple fields of study have tackled this challenge and developed different ways of measuring delinquency and criminal conduct giving rise to the criminal knowledge that is essential in all developed societies (e.g., crime statistics, criminal careers, risk factors, interventions effectiveness, etc.). Nevertheless, current measures of crime are recognized as being deeply flawed, and it became a common practice in criminology studies to attach warning labels about potential validity problems and that different methods may result in different estimates of crime.

The two most used measurement techniques in criminological science are official records (provided by police, courts, or prisons) and self-reports of offending. Considering that not all crimes are reported to the police, that not all reported crimes are recorded, not all recorded crimes result in convictions, and that not all convictions result in imprisonment, official records presents itself as a filtered and biased measure of crime. On the other hand, self-reports of offending seem to provide better estimates of the prevalence and mean frequency of criminal behavior [2].

Nevertheless, self-reports of human behavior can be affected by a wide array of factors and criminological research on self-report methodology is severely underexplored. Research on sensitive questions and how questions shape the answers of participants has developed a lot in the last few decades. Unfortunately, sensitive questions research commonly includes questions about income, voting, sexual behavior, and drug use, and only very rarely are selfreports of offensive behavior included. In a recent review, Gomes HS, et al. [3] found a total of 21 experiments since 1974 studying different types of biases in self-reports of offending.

Asking someone to report past offenses can be seen as an invasion of privacy which often results in socially desirable answers and underreporting of undesired behaviors. By developing experimental studies, in which participants are randomly allocated to different experimental conditions (e.g. face-to-face interviews vs. anonymous self-administered questionnaires), researchers can compare offending estimates and deduce which are the better ways to measure self-reported offending. In other words, since we expect participants to underreport sensitive behaviors, experimental conditions which result in a higher prevalence of criminal behavior are considered the ones providing the best estimate (i.e. the one closest to the real amount of behavior). This is what researchers called the ‘more is better’ assumption.

Despite the small amount of research on this topic, evidence suggests that participants report of offending are affected by modes of administration, characteristics of the interviewer, anonymity, setting, bogus pipeline, response format, and size of the questionnaire [3]. However, many of these experiments lack replication and many other potential biases remain untested. We believe that by continuing to develop experiments of selfreport methods we can improve on crime measurements and, consequently, improving criminological knowledge.

None.

This study was conducted at the Psychology Research Centre [UID/PSI/01662/2013], University of Minho, and supported by the Portuguese Foundation for Science and Technology and the Portuguese Ministry of Science, Technology and Higher Education through national funds and co-financed by FEDER through COMPETE2020 under the PT2020 Partnership Agreement [POCI- 01-0145-FEDER-007653]. The author was supported by a doctoral grant from the Portuguese Foundation for Science and Technology [FCT – SFRH/BD/122919/2016].

1. Ferraro KF, Grange RL (1987) The Measurement of Fear of Crime. Sociological Inquiry 57(1): 70-97.
2. Gomes HS, Maia A, Farrington DP (2018) Measuring offending: selfreports, official records, systematic observation and experimentation. Crime Psychology Review 4(1): 26-44.
3. Gomes HS, Farrington DP, Maia A, Krohn M (in press) Measurement bias in self-reports of offending: A systematic review of experiments. Manuscript submitted to publication.