study of criminality, and the study of the juvenile justice and criminal justice systems.
Sellin made the simple but critically important observation that “the value of a crime rate for index purposes decreases as the distance from the crime itself in terms of procedure increases” (1931:337). Thus, prison data are less useful than court or police data as a measure of actual delinquent or criminal behavior. Moreover, the reactions of the juvenile and criminal justice systems often rely on information from victims or witnesses of crime. It does not take an expert on crime to recognize that a substantial amount of crime is not reported and, if reported, is not officially recorded. Thus, reliance on official sources introduces a number of layers of potential bias between the actual behavior and the data. Yet, through the first half of the twentieth century, our understanding of the behavior of criminals and those who reacted to crime was based almost entirely on official data.
While researchers were aware of many of these limitations, the dilemma they faced was how to obtain valid information on crime that was closer to the source of the behavior. Observing the behavior taking place would be one method of doing so, but given the illegal nature of the behavior and the potential consequences if caught committing the behavior, participants in crime are reluctant to have their behavior observed. Even when observational studies have been conducted—for example, gang studies (e.g., Thrasher, 1927)—researchers could observe only a very small portion of the crimes that took place. Hence, observational studies had limited utility in describing the distribution and patterns of criminal behavior.
If one could not observe the behavior taking place, self-reports of delinquent and criminal behavior would be the data source nearest to the actual behavior. There was great skepticism, however, about whether respondents would be willing to tell researchers about their participation in illegal behaviors. Early studies (Porterfield, 1943; Wallerstein and Wylie, 1947) found that not only were respondents willing to self-report their delinquency and criminal behavior, they did so in surprising numbers.
Since those very early studies, the self-report methodology has become much more sophisticated in design, making it more reliable and valid and extending its applicability to myriad issues. Much work has been done to improve the reliability and validity of self-reports, including the introduction of specialized techniques intended to enhance the quality of self-report data. These developments have made self-report studies an integral part of the way crime and delinquency are studied.
Although the self-report method began with the contributions of