U.S. Department of Justice
Office of Justice Programs
Bureau of Justice Statistics

Bureau of Justice Statistics Bulletin

Technical Background on the Redesigned National
Crime Victimization Survey
October 30, 1994, NCJ-151172

Full text with tables available from:
Bureau of Justice Statistics Clearinghouse
800-732-3277 (fax number for report orders and mail
list signup only: 410-792-4358)
Box 179
Annapolis Junction, MD. 20701-0179

U.S.Department of Justice
Office of Justice Programs

Technical Background on the Redesigned National
Crime Victimization Survey

Prepared by the U.S. Bureau of the Census

Bureau of Justice Statistics
Washington, DC  20531
For information contact Jay Hoover
Telephone:  (202) 307-1132

-----------
Contents
-----------

Purpose of these briefing materials

Redesigning the National Crime Victimization Survey

Implementing the new questionnaire and procedures

Comparing new and old questionnaires and procedures

Reasons for differences in crime rates between the
new and old methods

Reasons for differences in the percent of crimes
reported to police between the new and old methods

Redesign of type of crime classification scheme

Overlap between the old and new NCVS methods



----------
Tables
----------

1.  1992 NCVS crime rates by type of crime

2.  Civilian population age 12 and over adjusted
for census population undercount   

3.  1992 NCVS percent of crime reported to police
by type of crime

4.  Changes in totals reflect the headings under
which offenses are counted


--------------------------------------
Purpose of these briefing materials
---------------------------------------

These briefing materials on the redesigned National
Crime Victimization Survey (NCVS) provide a summary
of the changes made to the questionnaire and
procedures and their impact.  The methods by which
these changes were phased in are presented.  A
detailed comparison of the new and old
questionnaires and procedures is discussed along
with reasons why these new methods produce higher
crime rates.  The new type of crime classification
scheme is presented.  Finally, the eventual method
for comparing crime estimates time series is
described.

----------------------------------------------
Redesigning the National Crime Victimization Survey
----------------------------------------------

The National Crime Victimization Survey (NCVS) -- a
major source of the nation's statistics on criminal
victimizations -- has undergone an extensive
redesign.  A collaborative effort on this redesign
among several institutions and agencies, including
the Bureau of Justice Statistics and the Bureau of
the Census, began in the late 1970's and has
focused principally on improving the accuracy and
utility of crime measurement.

The National Crime Victimization Survey began in
1972.  It collects victimization data from a sample
of about 100,000 individuals living in about 50,000
households.  Prior to the redesign, the
victimizations were categorized as personal crimes
of violence (rape, robbery, and assault), personal
crimes of theft, and household crimes (burglary,
household larceny, and motor vehicle theft).

In the mid 1970's, the National Academy of Sciences
reviewed the National Crime Victimization Survey. 
While the survey was found to be an effective
instrument for measuring crime, reviewers
identified aspects of the methodology and scope of
the NCVS that could be improved. 
They proposed that research investigate the
following:
* an enhanced screening section that would better
stimulate respondents' recall of victimizations,
thus reducing underreporting because of forgotten
incidents;
* screening questions that would sharpen the
concepts of criminal victimization and diminish the
effects of subjective interpretations of the survey
questions;
* additional questions on the nature and
consequences of victimizations that would yield
more useful data for analysis.

In response, the Bureau of Justice Statistics
sponsored a research consortium to investigate the
issues raised in the review and to make
recommendations that would improve the accuracy and
utility of the NCVS.  The redesign consortium
completed its work in 1985.

More recently, the issue of specifically improving
the measurement of sex crimes and domestic violence
resulted in the formation of a special committee
associated with the American Statistical
Association's Committee on Law and Justice
Statistics.  This committee developed enhanced
questions on rape, sexual assault, and domestic
violence to get better estimates of these crimes
that are difficult to measure.

----------------------------------------------
Implementing the new questionnaire and procedures
----------------------------------------------
The Bureau of Justice Statistics and the Bureau of
the Census examined the utility, feasibility and
cost of the consortium's redesign recommendations
and developed new questionnaires and procedures to
be implemented.  In 1986, a number of important
changes judged to be non-rate-affecting were
introduced.  Most of these changes were made to the
incident report, which contains questions designed
to obtain data on characteristics and circumstances
of reported crime incidents.  The changes included
more specific questions about the victim's behavior
during an incident and the extent to which those
actions affected the outcome, new questions dealing
with perceived substance abuse by offenders, and
expanded coding on other topics, such as offender
weapon use.  The Bureau of Justice Statistics
released several reports analyzing the new data.

More comprehensive changes were tested and phased
in on a more gradual basis.  These changes were
considered rate-affecting because of their expected
impact on the number of crimes reported in the
National Crime Victimization Survey.  They include
a substantial reworking of the screener (the part
of the questionnaire that ascertains whether the
respondent has been a crime victim) and survey
procedures (such as the use of computer-assisted
telephone interviewing and redefining series
crimes).  Based on test results that were
encouraging, the new questionnaire and procedures
were phased in from January 1992 through June 1993
in half the sample areas.  This overlap phase-in
method of the old to the new allows the Bureau of
Justice Statistics to continue to produce estimates
of annual change in crime rates and enables
analysts to assess the effect of the new
questionnaire and procedures on crime measures. 
Since July 1993 the redesigned methods have been
used in all sample areas.

----------------------------------------------
Comparing new and old questionnaires and procedures
----------------------------------------------

This comparison is limited to differences that
existed during the overlap period (January
1992-June 1993).

New methods

* New questionnaire screener
* Computer-assisted telephone interviewing for 30%
of sample
* Series crime redefined as 6 or more related
incidents
* Survey population estimates are ratio adjusted to
known population figures adjusted for the estimated
census population undercount.

Old methods

* Old questionnaire screener
* Computer-assisted telephone interviewing for 5%
of sample
* Series crime defined as three or more related
incidents
* Survey population estimates are ratio adjusted to
unadjusted population figures.

----------------------------------------------
Reasons for differences in crime rates between the
new and old methods
----------------------------------------------

The reason for differences in crime rates between
the new and old methods relates to the differences
between the new and old questionnaire and
procedures discussed above.  The screener
differences vary by type of crime and will be
addressed separately, followed by discussions of
the three procedural differences.

----------
Screener
----------

Even though many changes to the screener may relate
to specific types of crimes, there are some changes
in the format that carry across all types of
crimes.  One is the avoidance of the yes/no
question-and-answer format of the old screener. 
The new screener uses a short-cues approach
throughout.  With a short-cues screener, the
respondent is provided an extended list of cues
regarding crime victimizations and situations in
which crime victimizations might have occurred. 
The idea is to provide respondents sufficient time
to recall victimizations (which are fairly rare)
and help in structuring the recall task before
being required to respond.  Another general change
in the new screener is the exclusion of criminal
terms and concepts found in the old screener.  

----------------------------------------------
Reasons for differences in violent crime rates
because of the new and old screener questions
----------------------------------------------

The new screener questions provide more specific
cues regarding kinds of items used as weapons and
kinds of offender actions that better define the
in-scope crimes of violence for the NCVS.  In
particular, the explicit cuing of rape and other
sexual assaults has been added to the new screener. 
A side-by-side comparison of the new and old
screener questions is provided.

Furthermore, two frames of reference have been
added or more explicitly defined in the new
screener.  The first relates to crimes being
committed by someone the respondent knows. The
second relates to the possible location of a crime
or activities the respondent may have been involved
in.  This screener question takes the few
sporadically mentioned cues of location/activity in
the old screener questions and creates another
specific frame of reference with a greatly expanded
list of location/activity cues.

--------------------------------
Violent crime screener questions
--------------------------------

New

1.  Has anyone attacked or threatened you in any of
these ways --

     a.  With any weapon, for instance, a gun or
knife -- 

     b.  With anything like a baseball bat, frying
pan, scissors, or stick --

     c.  By something thrown, such as a rock or
bottle -- 

     d.  Include any grabbing, punching, or
choking,

     e.  Any rape, attempted rape or other type of
sexual attack --

     f.  Any face to face threats --

     OR 

     g.  Any attack or threat or use of force by
anyone at all?  Please mention it even if you are
not certain it was a crime.

2.  Incidents involving forced or unwanted sexual
acts are often difficult to talk about.  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 

Old

1.  Did anyone take something directly from you by
using force, such as by a stickup, mugging or
threat?

2.  Did anyone TRY to rob you by using force or
threatening to harm you?

3.  Did anyone beat you up, attack you or hit you
with something, such as a rock or bottle?

4.  Were you knifed, shot at, or attacked with some
other weapon by anyone at all?

5.  Did anyone THREATEN to beat you up or THREATEN
you with a knife, gun, or some other weapon, NOT
including telephone threats?

6.  Did anyone TRY to attack you in some other way?

----------------------------------------
All types of crimes screener questions
----------------------------------------

New

1.  Were you attacked or threatened OR did you have
something stolen from you --

     a.  At home including the porch or yard -- 

     b.  At or near a friend's, relative's, or
neighbor's home -- 

     c.  At work or school --

     d.  In places such as a storage shed or
laundry room, a shopping mall, restaurant, bank or
airport --

     e.  While riding in any vehicle --

     f.  On the street or in a parking lot -- 

     g.  At such places as a party, theater, gym,
picnic area, bowling lanes, or while fishing or
hunting --

     OR 

     h.  Did anyone ATTEMPT to attack or attempt to
steal anything belonging to you from any of these
places? 


2.  People often don't think of incidents committed
by someone they know.  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? 

3.  Did you call the police to report something
that happened to YOU which you thought was a crime? 

4.  Did anything happen to you which you thought
was a crime, but did NOT report to the police? 


Old

1.  Was anything stolen from you while your were
away from home, for instance, at work, in a theater
or restaurant, or while traveling?

2.  Did you call the police to report something
that happened to YOU which you thought was a crime?

3.  Did anything happen to YOU which you thought
was a crime, but did NOT report to the police?

----------------------------------------------
Reasons for differences in crime of theft and
household larceny rates because of the new and old
screener questions
----------------------------------------------

The number of cues in the new screener has been
greatly increased in an effort to expand the frame
of reference of things that may have been stolen.

As with crimes of violence, the two new frames of
reference (someone you know and location/activity)
provide many more cues to assist respondents in
recalling crimes of theft and possibly household
larcenies.

----------------------------------------------
Crimes of theft and household larceny screener
questions
----------------------------------------------

New

1.  Was something belonging to YOU stolen, such as
-- 

     a.  Things that you carry, like luggage, a
wallet, purse, briefcase, book -- 

     b.  Clothing, jewelry, or calculator -- 

     c.  Bicycle or sports equipment --

     d.  Things in your house -- like a TV, stereo,
or tools -- 

     e.  Things outside your home such as a garden
hose or lawn furniture -- 

     f.  Things belonging to children in the
household --
     g.  Things from a vehicle, such as a package,
groceries, camera, or cassette tapes -- 

     OR 

     h.  Did anyone ATTEMPT to steal anything
belonging to you? 


2.  About your motor vehicles 

     a.  Did anyone steal any parts such as a tire,
tape deck, hubcap or battery? 

     b.  Did anyone steal any gas from them? 

     c.  Did anyone ATTEMPT to steal parts attached
to them?

Old

1.  Was anything at all stolen that is kept outside
your home, or happened to be left out, such as a
bicycle, a garden hose, or lawn furniture?

2.  Did anyone steal, or TRY to steal parts
attached to it, such as a battery, hubcaps, tape
deck, etc.?

3.  Did you have your (pocket picked/purse
snatched)?

4.  Did anyone steal things that belonged to you
from inside ANY car or truck, such as packages or
clothing?

5.  Was anything stolen from you while you were
away from home, for instance at work, in a theater
or restaurant, or while traveling?

6.  Was anything at all stolen from you?

7.  Did you find any evidence that someone
ATTEMPTED to steal something that belonged to you?
----------------------------------------------
Reasons for differences in burglary rates because
of the new and old screener questions
----------------------------------------------

In general, the same frame of reference is
established for burglary in the new and old
screener.  However, the new screener has several
more specific cues.  These additional cues relate
to how the offender might have gotten into or
attempted to get into the respondent's home and/or
other types of buildings that may be on the
respondent's property.

----------------------------
Burglary screener questions
----------------------------

New

1.  Has somebody -- 

     a.  Broken in or ATTEMPTED to break into your
home by forcing a door or window, pushing past
someone, jimmying a lock, cutting a screen, or
entering through an open door or window? 

     b.  Has anyone illegally gotten in or tried to
get into a garage, shed or storage room? 

     OR 

     c.  Illegally gotten in or tried to get into a
hotel or motel room or vacation home where you were
staying? 

Old

1.  Did anyone break into or somehow illegally get
into your home, garage, or another building on your
property?

2.  Did you find a door jimmied, a lock forced, or
any other signs of an ATTEMPTED break in?

3.  Did anyone take something belonging to you or
any member of this household, from a friend's or
relative's home, a hotel or motel, or vacation
home?

---------------------------
Motor vehicle theft rates
---------------------------

There is no significant difference in motor vehicle
thefts rates between the new and old methods.  One
reason is that the new and old screener questions
are very similar.  Another reason is that motor
vehicle thefts are highly salient events
(demonstrated by the fact that they have the
highest percent reported to police), suggesting
little room for improvement in their measurement. 
Similar results were observed in the
Computer-Assisted Telephone Interviewing (CATI)
research.  While CATI increased ratios for most
types of crime, it had no significant effect on
motor vehicle theft rates.

----------------------------------------
Motor vehicle theft screener questions
----------------------------------------

New

1.  Was it --

     a.  Stolen or used without permission? 

     b.  Did anyone ATTEMPT to steal any vehicles? 

Old

1.  Did anyone steal, TRY to steal, or use it
without permission?

----------------------------------------------
Reasons for differences in crime rates because of
the new and old procedures
----------------------------------------------

Computer-assisted telephone interviewing (CATI)

The use of CATI from a centralized telephone
facility has been previously shown to increase the
number of reported crimes.  The combined effect of
centralization (ability to monitor interviewers)
and computerization of the questionnaire are
generally believed to help standardize the
interviewer-respondent interaction leading to
higher and more realistic CATI crime rates.  Even
though this CATI effect was explicitly measured
only with the old questionnaire, there is evidence
that the effect applies to the new questionnaire as
well. Specifically, the use of CATI increased the
rates of crimes of violence, crimes of theft, and
household larceny by about 15-20% and burglary by
about 10%.  CATI's effect on motor vehicle thefts
was negligible.

Series crimes

Under old procedures, a series crime was defined as
three or more similar but separate crimes which the
victim is unable to recall individually or describe
in detail to an interviewer.  These crimes have
been excluded from annual estimates because the
victims were unable to provide details for each
event and a consensus was never reached on how to
handle them.  Special reports have included series
crimes as one victimization.

Recognizing the difficulty that series crimes pose
in terms of estimation, the Bureau of Justice
Statistics decided for the new procedures to raise
the minimum threshold for accepting a series report
from three to six incidents.  This decision was
based on a special study of series crimes which
showed that respondents were able to complete
separate incident reports for as many as 5
incidents.  The result is that if a respondent
reports three to five similar incidents to an
interviewer, data on each incident are collected. 
While difficult to assess, the effect on crime
rates is probably a small increase of 1-5% for most
types of crime.  The notable exceptions are
assaults and some types of thefts, where the
"increase in crime rates may be in the 10-15%
range.

Adjusted population controls

Concurrent with the introduction of the new
questionnaire is the use of NVCS population
controls that have been adjusted for census
population undercount.  Unadjusted population
controls were used for the old questionnaire.  The
shift toward blacks and younger population groups
(both of which traditionally have higher than
average victimization rates) increases the rates of
crime categories sensitive to changes in the race
or age distribution (such as crimes of violence) by
1-2%).

----------------------------------------------
Reasons for differences in the percent of crimes
reported to police between the new and old methods
----------------------------------------------

In general, the percent of crimes reported to
police are lower with the new methods, in
particular for assaults.

The lower percentages with the new methods comes
from the fact that the increases in crimes not
reported to police are greater than the increases
for crimes reported to police.  There are several
inter-related reasons for this differential impact. 
One is the more expanded cuing of less serious
crimes (crimes less likely to be reported to the
police), which were not as well defined in the old
screener.  Another is that crimes reported to
police may be more memorable and less subject to
measurement error reduction.

----------------------------------------------
Redesign of type of crime classification scheme
----------------------------------------------

A major reclassification scheme has shifted most of
what were previously categorized as personal crimes
of theft into property crimes of theft.  Under the
old scheme, theft was characterized as a personal
or household crime based on location of the
incident.  If an item were stolen from the grounds
of a home, it was considered a household theft; if
the same item were stolen from someplace away from
the home it was considered a personal theft. This
distinction was rather arbitrary and unwieldy,
since many items are jointly owned by members of a
household.  The redesigned NCVS classifies all
thefts as household thefts unless there was contact
between victim and offender.  Personal thefts with
contact (purse snatching and pocket picking) are
now the only types of theft that are categorized as
personal theft.

----------------------------------------------
Overlap between the old and new NCVS methods
----------------------------------------------

As discussed previously, an integral part of the
planned transition from the old methods to the new
methods of conducting the NCVS was to include a
substantial overlap period in which both methods
were implemented concurrently.  Besides being used
for comparing crime estimates, the overlap data can
be used to extend earlier time trends data. 
Statistical models will be developed to adjust for
the effects of the new methods on victimization
reporting.  Adjustment factors will be estimated at
least for the major crime categories and possibly
for other important variables if reliable
differences are found.