It is the major tool used by BJS to provide statistics on criminal victimizations, covering rape, sexual assault, robbery, assault, theft, household burglary, and motor vehicle theft. It is the source of data for an annual BJS publication, Criminal Victimization, and numerous other regular and special reports. It also focuses attention on the characteristics of the victims of crime, including the nature of their victimizations. This chapter first briefly describes the history and development of the NCVS, including a major redesign in It then provides some descriptive details about the survey, including the target population and sample design, the data collection process, the survey instruments, the definitions used for rape and sexual assault, the estimation process, and the products.
This chapter is descriptive in nature: The panel's assessment of various features of the survey is the subject of Chapters 7 , 8 , and 9. In reading this chapter, it is important to keep in mind that the NCVS is an omnibus survey, covering many types of criminal victimizations, not just rape and sexual assault. However, to the extent possible and in keeping with the panel's charge, this chapter and the entire report are focused on the issues relevant to those two victimizations. The commission reported that the UCR was useful in many ways, but it noted several critical concerns with having just one source of crime statistics.
One concern was that the UCR was a summary of only those crimes reported to and recorded by police and not all crimes see Chapter 3. Secondly, the commission found that the UCR administrative statistics were open to possible manipulation and misrepresentation. Finally, the commission said, the UCR lacked information about the victims, the victimization incidents, and the offenders that is needed to develop effective policy choices.
The commission recommended the development of a national crime survey President's Commission on Law Enforcement and the Administration of Justice, ; Rennison and Rand, Work on the National Crime Survey NCS , predecessor of the NCVS, began soon afterwards with small-scale field tests of questions asked of victims of crimes that had been reported to police.
A questionnaire was developed from these tests, which was initially implemented as a supplement to the Census Bureau's Quarterly Household Survey in These supplements served as a way to further develop concepts and questions; they were not used to produce BJS published reports.
In July the new NCS was fielded. The core had a sample of 72, households and noninstitutionalized group quarters. BJS established a redesign consortium, and small-scale changes to the survey and its instruments were implemented in Considerable cognitive work was undertaken as part of this redesign, much of which focused on understanding and testing screener strategies to increase reported incidents.
In the NCS the screener directly asked a respondent about several but not all types of possible victimizations. According to the Bureau of Justice Statistics , pp. The aim of these innovations was both to elicit increased reporting of crime incidents and to structure the recall task to a greater degree, so that cognitive and subcultural differences among respondents would have a smaller impact on the reporting of crime incidents. Other topics, such as bounding, reference period, interview-to-interview recounting, ways to enhance the reliability of dating incidents, and series crimes were analyzed during this redesign process.
More details are available from Bureau of Justice Statistics Following this development, a three-wave national pretest of the redesigned victimization survey was fielded in The new survey questionnaire included revisions that were viewed as a major improvement over its predecessor Bachman and Taylor, Based on cognitive research demonstrating that long recall periods yielded poorer reports and that a reference period of 12 months generally reduced the reporting of all criminal incidents by approximately 30 percent Cantor and Lynch, , a 6-month reference period was retained.
The NCVS was fully implemented in with 70, households and , individuals interviewed. BJS must ensure that the nation has quality annual estimates of levels and changes in criminal victimization.
Congress and the administration should ensure that BJS has a budget that is adequate to field a survey that satisfies that goal. In , 79, households and , individuals were interviewed. It includes Bureau of Justice Statistics, b , p. Crew members of merchant vessels, Armed Forces personnel living in military barracks, and institutionalized persons, such as correctional facility inmates, were not included in the scope of this survey.
The design challenge for the NCVS is to estimate the number of victimizations for the target population that have occurred within the past year and the change from the previous year. The victimizations include events that range from statistically common, such as theft This type of situation is discussed in a classic textbook on sampling Hansen, Hurwitz, and Madow, , p. The result is a nationally representative sample of individuals identified for data collection. Table provides a summary of the two main stages of this multistage design.
The primary sampling units PSUs in the first selection stage are small groups of neighboring counties, or large individual counties or metropolitan areas. The remaining PSUs are grouped into strata with similar geographic and demographic characteristics 3 as determined by the most recent census, and then sampled with probability proportional to their population size. Secondary sampling units SSUs are individual residential units, which are sampled within each selected PSU separately from each of four nonoverlapping list frames of eligible units.
The four frames called unit, permit, area, and noninstitutionalized group quarters are used to maximize the population coverage of the NCVS sample. The second stage sample is drawn with a systematic selection of these clusters from each frame. This sampling process is similar to that used for the Current Population Survey. For field interviewing, the overall sample is divided into six rotation groups, and each rotation group is further divided into six equal collection panels.
A single panel from each rotation group is contacted each month, allowing the entire rotation group to be contacted within 6 months with an equal distribution across months. Table displays the rotation pattern for a single rotation group, showing the interview month I and the months x that are included in the reference period for that interview. Because the survey is continuous, newly constructed housing units are selected as described and assigned to rotation groups and panels for subsequent incorporation into the sample.
A new rotation group enters the sample every 6 months, replacing a group phased out. With this overall design, each household in a rotation group is interviewed once every 6 months for a total of seven interviews.
The sample is address based, so that if a household or household member moves during the years of the panel, the interviews continue with the current household members who reside at the sampled address. For subsequent interviews, the field representative may, and most often does, conduct the interview by telephone; personal interviews are conducted subsequently on the basis of a respondent's request and as needed to maintain continued response.
Both in-person and telephone interviewing use computer-assisted survey instruments. Overall, 55 percent of person-level interviews in were conducted over the telephone. The NCVS data collection protocol calls for the direct interviewing of each person 12 years or older in the household, with interviews held separately for each household member. Proxy interviewing instead of direct interviewing is permissible for minors when a knowledgeable household member insists they not be interviewed directly ; incapacitated persons; and individuals absent from the household during the entire period of field interviewing.
In the second part of the interview, detailed information about any incident reported during the screening process is collected. The process is described in more detail below.
The control card is used to build a roster of household members, to determine eligibility to be interviewed, and to obtain basic information about the sample unit, including a record of visits, telephone calls, interviews, and reasons for any noninterview.
It lists the name, age, gender, marital status, education, and relationships of all persons residing in a household. The importance of the control card lies in its brief description of all victimizations reported by household members in each interview. It serves as a quick reference during future interviews to ensure that victimizations previously counted are not reported again in error.
The basic screen questionnaire is used to screen for incidents that occurred during the 6-month reference period in which the individual household member may have been victimized. An incident report is completed for each event recorded in the basic screen questionnaire.
The report collects detailed information about each victimization, including the time, date, and place; information about the offender, including any relationship to the victim; circumstances of the incident, such as whether a weapon was used; consequences to the victim, including injury and loss of or damage to property; and whether the incident was reported to police.
The incident report, along with the screening report, is subsequently used to categorize the incident as to whether it is a crime, and if so, what type of crime. This process is discussed in greater detail in Chapter 7. Cue Screening Questions During the screening phase, respondents are asked both directly and indirectly about potential victimizations through short cue screening questions.
In an omnibus victimization survey like the NCVS, it would be difficult and burdensome to list each specific possible type of victimization in the screening questionnaire. Instead the screener contains cues designed to trigger memories of victimizations through cues related to particular contexts, locations, weapons, and offenders. A respondent may report any victimization at any point during the screening process. Several cue screening questions deal specifically with physical attacks, threats, or sexual activity.
Since [end date for 6-month reference period], were you attacked or threatened OR did you have something stolen from you: Other than any incidents already mentioned, has anyone attacked or threatened you in any of these ways: Please mention it even if you are not certain it was a crime. People often don't think of incidents committed by someone they know. Other than any incidents already mentioned, did you have something stolen from you OR were you attacked or threatened by a someone at work or school, b a neighbor or friend, c a relative or family member, d any other person you've met or known?
Incidents involving forced or unwanted sexual acts are often difficult to talk about. Other than any incidents already mentioned, have you been forced or coerced to engage in unwanted sexual activity by a someone you didn't know before, b a casual acquaintance? OR c someone you know well? During the last 6 months [other than any incidents already mentioned , did you call the police to report something that happened to YOU which you thought was a crime?
If the respondent replies yes to any of the cue screening questions, then he or she is asked to briefly describe in his or her own words what happened. Incident Report In the incident report, the respondent is further queried in detail about each incident reported in the screener. There are questions that relate to the location of the incident, weapon used if any , injuries, medical care and expenses, distress as a victim, others present during the incident, etc.
Listed below are questions that deal specifically with physical attacks, threats, or sexual activity. Did the offender hit you, knock you down or actually attack you in any way? Did the offender TRY to attack you? If the respondent says an attack was attempted or threatened, then she or he is asked: How did the offender TRY to attack you?
How were you threatened? If the respondent reports an unwanted sexual contact, then she or he is asked: You mentioned some type of unwanted sexual contact with force. Do you mean forced or coerced sexual intercourse including attempts? If the respondent mentions rape, then he or she is asked: Do you mean forced or coerced sexual intercourse?
If the response is no, then he or she is asked: What do you mean?