THE NATIONAL CRIME VICTIMIZATION SURVEY REDESIGN: NEW
    UNDERSTANDINGS OF VICTIMIZATION DYNAMICS AND MEASUREMENT

                               by
              Bruce M. Taylor and Michael R. Rand
                  Bureau of Justice Statistics

Paper prepared for presentation at the 1995 ASA Annual Meeting, August 13-17, 1995 in Orlando,
Florida.  The views expressed are attributable to the authors and do not necessarily reflect positions
of the Department of Justice or the Bureau of Justice Statistics.
THE NATIONAL CRIME VICTIMIZATION SURVEY REDESIGN: NEW
UNDERSTANDINGS OF VICTIMIZATION DYNAMICS AND MEASUREMENT

Bruce M. Taylor and Michael R. Rand
Bureau of Justice Statistics, 633 Indiana Ave. NW, Washington, D.C. 20531

KEY WORDS:  Reporting, Prevalence, Response Error

The National Crime Victimization Survey (NCVS) has been extensively revised after a multi-year
effort to evaluate the victimization characteristics it measured and methods used to collect survey
data.  The impetus for this project came from several sources, beginning with an evaluation of the
survey by the National Academy of Sciences in the mid-1970's.  This paper will revisit some of the
issues that led BJS to redesign the survey and will attempt to evaluate how well the revised survey
addresses these problems, which include completeness and accuracy of victimization measurement,
response error, and reporting artifacts.  The paper will also address how the redesigned affects our
ability to meet existing objectives for the survey, and will outline how it creates new options for the
study of victimization.Introduction

The National Crime Victimization Survey (NCVS) was inaugurated in July 1972 and was instituted
to satisfy two broad goals in providing information on the incidence of crime and its effects on
victims:

     To create a time series tracing changes both in the incidence of crime and in the association
     between criminal victimization and attributes of victims, offenders, and crime incident
     characteristics.

     To create a vehicle that would allow study of particular research questions related to
     criminal victimizations, such as the relationship of victims to offenders, the cost of crime,
     and the vulnerability of various types of individuals to victimization.  

The NCVS was intended to complement information available from the FBI's Uniform Crime
Reports series by collecting data on crimes not reported to the police and by providing more
detailed information on victims and victimization incidents.

After several years experience with the survey, the Department of Justice asked the National
Academy of Sciences to perform an evaluation of the survey, and these findings were published in
1976.  As a response to the Academy's findings and subsequent internal reviews, the Bureau of
Justice Statistics began a project to redesign the survey in 1979.  This project comprised three
distinct phases:

     A contractual research and development effort performed by a consortium of experts in
     survey design, statistics, criminology, and victimization, headed by the Bureau of Social
     Science Research in Washington, D.C. (1979-85)

     Further testing and evaluation by the Census Bureau to produce the operation questionnaire
     and field procedures.  (1985-89)

     Phase-in of survey revisions.  Changes judged to be rate affecting were instituted in 1986. 
     Rate-affecting changes were phased in gradually from 1989-93.

The first annual change estimates using data from the fully redesigned survey were released in
November, 1995.

Sixteen years after the inauguration of this project, it seems useful now to examine what its
outcomes have been and what its impact has been on the quality and utility of NCVS data.  This
paper will address these questions and will be organized around four major themes:

I.   Completeness and accuracy of victimization measurement.
II.  Reduction in reporting artifacts.
III. Improvement in the survey's ability to meet existing objectives.
IV.  New options for the study of victimization created by the redesign.

I.  Completeness and accuracy of victimization measurement

The NCVS Screener

The NCVS questionnaire is divided into three sections:

     a control card that records household information, interview history, and information on
     reported crime incidents to "bound" reports in subsequent interviews.

     a screener that flags whether a household or personal victimization has occurred during the
     six month period before the interview.  This vehicle also records information on the
     interview, the household, and  individual respondents.  A screener is filled for each eligible
     respondent in the household.

     a crime incident form that records data on the characteristics of incidents reported by
     respondents in response to screener questions.  One incident form is filled for each
     incident.

Perhaps the single most pronounced change to the survey was the total revision of the screener.  A
number of different screening strategies were tested during the research and development phase of
the redesign project, with the aim of improving the respondent's ability to define, search for, recall,
and report victimizations suffered during the reference period. The most effective approach was to
pepper respondents with a number of short cues to evoke the context in which victimizations
might occur, including types of places where an attack could take place, possible relationships to the
offender, types of property that might have been stolen, and types of weapons that might have
been used in an attack.

In addition to other procedural changes, this screener revision resulted in an increase of 48% in
rates of personal crimes, 54% in violent crime, and 23% in property crime, as measured by a split
ballot comparison of old and new methods in 1992.  One might expect that this increase would
occur at the margin - those crimes that might be judged less severe because they resulted in less
injury or property loss or because they were not reported to police.  To some degree, this is the
case:

     Thefts of less than $50 showed a 47% improvement in rates, compared to 18% for those
     incidents in which $250 or more was lost.

     Simple assaults showed a 77% improvement, compared to 24% for aggravated assaults.

     Rates for aggravated assaults not reported to police showed a 47% improvement, compared
     to a nonsignificant change for aggravated assaults reported to police.  Rates for simple
     assault not reported were 99% higher with the new method, compared to 49% higher for
     simple assaults that were reported.

     Overall Robbery, which is potentially the most severe nonsexual crime measured by the
     NCVS, showed no significant method effect.  Robbery, however, is probably least sensitive
     to question design changes, because its context is arguably the least ambiguous of all crimes
     measured by the NCVS: An offender takes or attempts to take a victim's property, using
     violence or the threat of violence.  

The good news is that method differences are not restricted to less severe crimes and still show
substantial, significant improvements for more severe property and personal crimes.  The screener
seems most effective at helping respondents define and report incidents that may fall in gray areas. 
These include incidents that may not be easily recalled because of their lesser severity, but also
because they may have occurred in contexts that may not routinely be associated with crime, such
as at work or home, or because the offender was a nonstranger.  For example new method rates for
crimes of violence show a 40% improvement for stranger crimes, but a 66% increase for crimes
committed by relatives and a 77% difference for those committed by acquaintances.  Although it is
impossible to attribute this these effects specifically to any particular design change, it is likely that
at least some of this difference in increases across types of relationship to offender is attributable to
a question on the new screener that asks:

"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 (Exclude telephone threats) -

(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?"

Sexual assault

Of all types of crime measured by the NCVS, rape and sexual assault measurement was subjected to
the most rigorous scrutiny.  As initially designed, the NCVS screener did not directly ask
respondents whether they had been raped.  Only if a respondent answered positively to one of the
initial screening questions regarding attack, attempted attack or threat of attack was an incident
form administered., and then only if a respondent was reluctant to provide details on the incident
did the interviewer ask whether a rape, attempted rape, or threat of rape  had occurred.  No
definition of rape was provided to the respondent.  

This question strategy was the result of judgments at the inception of the survey in 1972 that direct
questioning of respondents regarding rape incidents would be invasive.  This climate changed over
subsequent years, and a number of other surveys included more direct measurement of rape and
special assault.  As part of the redesign this approach to rape measurement was reevaluated, with
the help of a panel convened by the American Statistical Association, and a number of changes
were introduced to help improve NCVS data on rape and sexual assault.  These revisions resulted
new method rates that were 323% higher for completed rape and 96% higher for attempted rape
than old method rates.  Major changes included adding a response code of "any rape, attempted
rape or other type of sexual attack" to the omnibus "attack and threat" screener question, including
the question about crimes committed by someone known to the respondent that was cited above,
and adding an additional question that allows hesitant respondents a second chance to report sexual
assaults:

"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?"

 
In addition, new response codes have been added to the incident form violent crime questions that
allow reporting of non-rape sexual assault and unwanted sexual contact.  A definition of rape is
provided to interviewers that may be used for reference or read to respondents.  The key elements
are physical or psychological coercion and the presence of any form of penetration.

Treatment of series crimes  

The original NCVS included a class of victimization labeled "series crimes."  These were groups of
three or more incidents that the respondent could not remember as discrete events.  Not only was
it impossible to accurately count series victimizations, but it was not clear whether these incidents
comprised the same type of crime.  Although the NCVS collected information on the most recent
victimization that would allow classification, it was nonetheless virtually impossible to use these
incidents in computing estimates, because of the lack of precision in counting and classifying them.The redesign project reexamined this class of victimization and made criteria more stringent for
classifying incidents collectively as a series crime.  The threshold was raised from three to six
incidents, and the respondent must indicate that these incidents are essentially the same type of
crime.  When a series classification is accepted, additional information is also collected on whether
these incidents occurred in the same place or were committed by the same person.  In addition, the
NCVS  attempts to determine the relationship of the offender to series victim and whether these
incidents are continuing.  One of the hypotheses proposed during the redesign was that series
crimes contained a disproportionate share of those crimes committed by offenders with ongoing
relationships to the victim, such as domestic violence.  These new questions will allow us to test this
hypothesis and provide some new information on the nature and duration of domestic violence
incidents, if this hypothesis is confirmed.

Period-to-period recounting

The NCVS utilizes a reference period of six months.  That is, the survey attempts to enumerate
victimization incidents that occurred to victims and their households in the previous six months. 
At it inception, the survey recorded information for the six months before the month in which the
interview occurred (e.g., January through June, if the interview was conducted in July).  If the
respondent had been victimized during the month in which the interview took place, he or she was
instructed to wait until the subsequent interview to report this information.  Although cutting off
reference periods at the beginning of the month produced clean temporal breaks for calculating
estimates, it had several unfortunate consequences.  First, waiting six months to report an incident
may result in less accurate information on dates and incident characteristics.  Second, this
instruction may appear nonsensical to the respondent, with a resulting negative effect on
respondent rapport and cooperation.

The NCVS redesign project suggested that respondents be asked to report incidents that had
occurred since the previous interview, and this change has been implemented.  This revision in field
procedures allows respondents to report incidents while details are fresh in their memories and also
provides a salient back-end anchor for reporting.  To produce estimates, the survey still prepares
files containing records for the six months prior to the month in which the interview occurs. 
Those incidents that occurred in the current month are not included in this file and are held for
processing with data from the subsequent interview.  If the incident is reported again in the next
reference period, interviewers have records on previously reported incidents that allow them to
unduplicate such reports.

Vandalism

The NCVS redesign project investigated a number of ways to expand the scope of crimes measured
by the survey.  Among these were arson and parental kidnaping.  BJS evaluated these suggestions
and rejected a number of them because of concerns about their expected rarity, which would make
it difficult to produce reliable estimates or analytical studies, or because of concerns about the
quality of data that could be collected about such crimes in a victim survey context.  BJS did
approve expansion of the NCVS to include measures of vandalism.  The revised NCVS does not
record vandalism as discrete incidents, as it does for other crimes, but collects information on the
type of property damaged and the costs of vandalism during the reference period.

II.  Reporting Artifacts

Since the inception of the survey, a number of reporting artifacts have been identified that relate to
larceny measures.  The original survey divided larceny into two broad categories -- household and
personal.  Personal larceny was further divided into "with contact" and "without contact" crimes. 
Contact crimes could be described as pocket picking and purse snatching.

Personal larcenies without contact and household larcenies were distinguished solely by the location
of the property when it was taken.  This somewhat arbitrary classification of larceny produced
several artifacts in larceny counting and reporting:

     The location of the property determined whether it was counted as a personal or household
     crime, with a corresponding effect on crime counts and rates.

     The rules for counting personal and household crimes vary in a way that may affect how or
     whether a larceny is counted at all, depending on how it is classified.

For example, if a child's bicycle is taken from the front yard or driveway of a home, the theft would
be classified as a household larceny with no other qualifications.  However, if the bicycle had been
taken from a schoolyard, it would be counted as a personal larceny, but only if the child was 12
years old and thus met the minimum age to be included as an NCVS respondent.  If the child was
less than 12, the theft would not be counted at all.

There were several other more subtle artifacts related to this classification rule for larceny. 
Consequently, the redesign project recommended that larceny classification schemes be revised to
eliminate this artifactual distinction between personal and household larceny.  Almost all larcenies
are now classified as thefts and are counted as property crimes.  The only exceptions are contact
thefts, which are classified as purse snatching and pocket-picking.

III.  Meeting existing objectives

The NCVS changes just described have several impacts on the quality of NCVS data:

     The revisions improve the coverage of the survey by enhancing its yield of victimization
     incidents.  This impact is particularly pronounced for sensitive crimes, such as sexual
     victimization or crimes committed by someone known by the victim, and for less salient
     crimes that may be more difficult to remember at first.

     The precision and reliability of NCVS data are enhanced by tightening the criteria for
     recording series incidents and by eliminating artifactual classifications of larceny.  By
     improving measures on sensitive crimes, the survey also improves the accuracy of estimates
     of the levels of these crimes.

     By increasing the number of victimization incidents reported, the NCVS revisions also
     improve the analytic utility of survey data.  Standard errors are reduced as a result of the
     increased number of cases, which makes the survey annual change measures more sensitive,
     and also improves the sample size available for topical analyses.

     The scope of the survey is enlarged to include vandalism and non-rape sexual victimization..

Consequently, as a package, the redesigned NCVS provides a more accurate, sensitive instrument
for measuring the likelihood and distribution of personal and household crime victimization.

IV.  New options for the study of victimization

In addition to improving the ability of the NCVS to measure overall personal and household crime
victimization, the redesign project has also expanded opportunities for analysis of the dynamics of
crime victimization.  These changes range from creating new predictor and outcome variables for
the on-going survey to special purpose files and supplements.

New predictor variables

The redesign project has resulted in a number of new variables that will be useful for illuminating
the dynamics of criminal victimization:

     Self-protection.  Victims are asked what they did, if anything, to protect themselves or their
     property during a personal victimization.  They are also asked whether they believed these
     actions helped or hurt their circumstances and how these actions hurt or helped.  Victims
     are also asked whether actions were taken before or after any injuries, to help determine
     whether the actions were precipitants or consequences of injury.  In addition, victims are
     asked whether actions of anyone other than the victim or offender who was present hurt or
     helped the situation.

     Gang membership.  The victim is asked whether the offender was a member of a street
     gang.

     Substance abuse.  The NCVS asks victims whether the offender was drinking or on drugs.

     Lifestyle variables related to risk.  All respondents are asked how often they go shopping,
     how often they spend the evening away from home, and how often they have ridden public
     transportation.

     Target hardening.  The designated household respondent is now asked whether the home
     has any special devices such as dead bolts, timers, or alarm systems to deter thieves or
     intruders.  The NCVS also asks whether a neighborhood watch or similar group is active in
     the neighborhood and whether someone from the household participates.

     Because the NCVS collects its data with a nationally representative sample, there are
     limitations on the subnational data it can provide, both because of privacy issues and the
     reliability of estimates that could be derived for subnational units.  The survey does include
     other generic variables that allow the analyst to perform analyses for places that share
     certain characteristics, such as size or MSA status.  The redesign project utilized these
     variables to produce a 14-level generic area model intended to allow disaggregation of
     NCVS data into meaningful subnational typologies.  BJS is currently evaluating this typology
     and hopes to release analyses utilizing it in the near future.

Supplements

The redesign project examined a number of issues related to the content of the survey.  One
outcome of this review was a suggestion that the fixed format, social indicator design of the survey
be relaxed to accommodate several classes of analytic needs:

     The NCVS was not achieving its potential as a resource for information on crime-related
     topics.   As the only large-scale nationally representative survey on crime, it would be a very
     useful vehicle to collect information on short-turnaround topical issues that were not part
     of its routine data collection.

     A number of questions, such as those related to employment, were not providing the quality
     of information that would be useful for analysis of crime dynamics.  BJS concluded that it
     would be preferable to delete these items from the regular survey and administer them in
     the context of short-term groups of questions that dealt more exhaustively with the topic. 
     This would be particularly useful for questions whose outcomes were not expected to
     change much from year to year.  

As a result, BJS decided to include the development of topical supplements as part of the regular
NCVS program.  In addition to supplements conducted early in the life of the survey, this
supplement effort has fielded two supplements related to school crime, the most recent being
funded by the National Center for Education Statistics.  BJS is evaluating future supplements
dealing with such topics as workplace violence, campus crime, and long-term consequences of
violent crime victimization.

C.  Development of new files

Another consequence of evaluating the survey has been the identification of special analytic uses for
NCVS data.  A number of these can be made more straightforward by developing special purpose
files.  In addition to rectangular files for crime incidents and rape victims that had already been
developed, a number of new files have been created or suggested as a result of this process:

     A longitudinal file was created that provides records for all housing units scheduled to
     receive all seven NCVS interviews in 1986-1991.  Although the NCVS utilizes a rotating
     panel design and is not therefore a fully longitudinal survey, this file allows analysts to
     examine some topics that would be very cumbersome with the regular annual files:

          Long-term patterns of victimization for sampled persons and housing units.

          The relationship between victimization and other life events, such as change in
          marital status, moving, leaving school, and employment.

          An examination of gross v. net changes in victimization from year to year.  I.e., to 
          what extent do last year's victims tend to be this year's?

     Other files under consideration include a file of violent crime victims, and a library of
     recodes used to produce published BJS analyses that have not been documented in BJS
     public use files.

Conclusion

As a result of the National Crime Victimization Survey redesign project, the NCVS is a substantially
different survey than it was 15 years ago.  It detects a substantially greater number of victimizations
than did the previous survey, the data are more accurate, particularly for more difficult to report
crimes, and the survey is more sensitive to temporal changes in these measures.
 
In addition to providing more accurate core data, the survey has enhanced its analytic utility by
providing new predictor variables and expanding the scope of crimes covered.  New files have also
been developed to make special purpose analyses easier.

Consistency is important to maintain the longitudinal comparability of NCVS data.  However, we
have tried to minimize the degree to which this goal translates into inflexibility in the survey's ability
to respond to new needs for criminal justice data.  As a result, BJS has made the regular design and
implementation of supplements an important component of the NCVS program.  As currently
constituted, the survey is well placed to provide useful, nationally representative crime
measurements well into the next century.