violence. Police deal with “suspects” who may or may not be the actual perpetrators of crimes; courts deal with “cases” or “defendants,” each of which involves one or more specific “charges,” and the connection between these labels and the individual “prisoners” who serve correctional sentences may be lost when authority for them transfers from the courts to the corrections system. An immediate consequence of this unit-of-measurement problem, which we discuss in this chapter and elsewhere in the report, is that measuring the flow of individuals through the justice system is extremely complicated. As a general concept, though, it is important to bear in mind that an approach to the “justice system” that focuses on tracking the experience of individual persons as they move through the system will present a different picture of justice processing than inferences drawn from one that focuses on the progression of “cases” through the set of discrete operations that either move them forward toward resolution or divert them out of the system.

There is no single way, and certainly no uniquely correct way, to conceptualize the criminal justice system. Hence, BJS’s task is to straddle a wide range of perspectives in selecting and defining its measurement programs, and to do so while ensuring collection at all (and widely varying, in themselves) levels of government.

In this chapter, we discuss the general challenge of measurement in the justice system. We begin by describing the basic model that we use as an orienting framework—the “funnel” model first developed by the President’s Commission on Law Enforcement and Administration of Justice (1967) (Section 2–A)—and discuss how BJS’s data collections roughly conform to that model (Section 2–B). Analysis of the funnel suggests some major gaps in U.S. justice statistics—and BJS’s statistical coverage in particular—which we describe in Section 2–C; these include difficulty in addressing new and emerging types of crime and contextual factors that apply to a wide range of criminal activities.


Many date the emergence of criminal justice research on the public scene with the release of the 1967 report of the President’s Commission on Law Enforcement and Administration of Justice, The Challenge of Crime in a Free Society. The report and its many companion volumes summarized what was known about criminal justice and called in virtually every section for more information about how the system operated.

The first chapter of the main report introduced as its organizing metaphor a flowchart presenting “a simple yet comprehensive view of the movement of cases through the criminal justice system” (President’s Com-

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