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The Crime Scene Justice Data and the Case of Multiple Files in GSS 18. Chuck Humphrey University of Alberta. Atlantic DLI Workshop April 20-21, 2006. Outline. a. Crime and Victimization Surveys b. Crime data in the context of the data reference interview

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the crime scene justice data and the case of multiple files in gss 18

The Crime SceneJustice Data and the Case of Multiple Files in GSS 18

Chuck Humphrey

University of Alberta

Atlantic DLI Workshop

April 20-21, 2006


a. Crime and Victimization Surveys

b. Crime data in the context of the data reference interview

c. Crime data structures from the context of the unit of observation

d. Working with GSS 18 as an example of a survey with multiple files


















justice system data
Justice System Data
  • Data collected from administrative data sources.*
    • 11 annual active surveys
    • 3 biennial active surveys
    • 5 one-time surveys

* See Justice Data Survey List handout.

population data
Population Data
  • Data collected from the Canadian population 15 years old and older.
    • 1 quinquennial active survey
      • General Social Survey on victimization
    • 3 one-time surveys
      • Crime Survey, 1981
      • Edmonton Crime Survey, 1985
      • Violence Against Women Survey, 1993

* See the Justice Data Survey List handout.

data reference interview
Data Reference Interview
  • Given the variety of Statistics Canada surveys used to gather information about crime and our judicial system, let’s review data reference interview strategies in light of what we know about justice data.
  • A typical data reference interview tries to distinguish between statistics and data, to identify likely sources for statistics and data and to determine how this information can be accessed.
data reference interview7
Data Reference Interview
  • Is the patron seeking statistics or data?

Statistics are processed data organized for display purposes.

Data, which are stored in files in a specific structure, require processing to be presented or displayed.



data reference interview8
Data Reference Interview
  • If the patron is looking for statistics, who or what agency would publish the numeric facts or figures that she/he wants?

[Think of statistics as having been published.]

Sources of Statistics:

 Official Statistics

 Government departments or agencies

 Non-official Statistics

 Non-governmental organizations

 Commercial sector sources

data reference interview9
Data Reference Interview
  • What format is most readily available to retrieve the statistics being sought? In what format would the patron like to receive the statistics?

Formats for Statistics:

 Print

 Online

 E-publications

 E-tables

 Databases

data reference interview10
Data Reference Interview
  • If the statistics cannot be found, is there a data source from which the statistics can be constructed?
  • Occasionally, a data source exists that can be processed to generate the statistical information being sought by the patron.

For example, Citizenship & Immigration Canada produce their Facts & Figures statistical report from the Landed Immigrant Database System (LIDS). Having access to LIDS allows one to produce many more tables than are published in Facts & Figures.

data reference interview11
Data Reference Interview
  • If the patron is looking for data, are they looking for aggregate data or microdata?

Aggregate data are statistics that have been organized into a data structure for further processing. The data structure will be organized around time, geography, social content or a combination of these characteristics.

Microdata consist of the information collected from the objects of the unit of observation and stored in a data structure for subsequent processing.

data reference interview12
Data Reference Interview
  • Who or what agency would produce and/or disseminate the data?

[Think of data as having been produced and disseminated.]

  • If data are found, how can they be accessed? Are they available in a public use file or are the data only available in a confidential file?
  • What kind of format does the patron prefer to work with the data?
data reference interview13
Data Reference Interview
  • Apply the strategies of the data reference interview with requests for crime or justice data in Canada.
    • Is one more likely to find statistics or data on justice and crime?
    • What kind of data is most likely to be available?
    • Who is most likely to publish Canadian justice statistics?
    • Who is most likely to produce and disseminate Canadian justice data?
data reference interview14
Data Reference Interview
  • Statistics and aggregate data are more readily available than microdata. The Canadian Centre for Justice Statistics (CCJS) compiles results from the surveys listed above and makes this information officially available.
    • A pilot project is currently underway in the Research Data Centres to provide access to the confidential files from the Uniform Crime Reporting Survey and the Homicide Survey.
data reference interview15
Data Reference Interview
  • For cross-provincial comparisons, CCJS information has standardized geographies and a common offence classification scheme. You may find police services and provincial justice departments also report local justice statistics.

For example, the Edmonton Police Service provides neighbourhood crime statistics on their website. On the other hand, the office of the Solicitor General of Alberta refers people to CCJS statistics.

data reference interview16
Data Reference Interview
  • What are your best sources to access Canadian justice statistics and data?
  • Apply the “continuum of access”

Statistics Canada website provides access to e-tables. The DSP provides access to e-publications and E-STAT access to CANSIM. DLI provides access to CCJS tables in Beyond 20/20 format and the GSS. The Research Data Centres provide access to some justice confidential data files.

data reference interview17
Data Reference Interview
  • The Justice Data Survey List handout includes a column identifying points of access for products from the various surveys.
  • A more comprehensive list of products is available from each survey’s IMBD entry.

For the Uniform Crime Reporting Survey, use the sidebar menu for “Additional Information” and find entries for the 2004 UCR Survey in the Daily, in summary tables in Canadian Statistics, in publications in the online catalogue and in tables from CANSIM.

unit of observation
Unit of Observation

If it’s data, it has structure.

  • One of the defining properties of data structure is the unit of observation.
  • The unit of observation consists of the objects about which information has been collected. This information describes each object and, in a sense, belongs to the object.
  • What are the units of observation in the active justice surveys mentioned above?
unit of observation20
Unit of Observation
  • Answers can be found in the IMDB entries for these surveys under the description of “Target population” and “Instrument design.”

All Canadian municipal, provincial and federal police services that were active on June 15th of the survey year.

All crimes that come to the attention of the police.

unit of observation21
Unit of Observation

All homicides that occur in Canada. Consists of three main questionnaires: Incident, Victim and Suspect.

All legal aid services in Canada.

All federal statute charges completed in youth courts of accused persons aged 12 to 17 years at the time of the offence.

unit of observation22
Unit of Observation

All provincial and territorial courts and federal courts comprising the Supreme Court of Canada, the Federal Court of Canada, the Tax Court of Canada and the Office of the Commissioner for Federal Judicial Affairs.

All federal statute charges in provincial and supreme criminal courts in Canada.

unit of observation23
Unit of Observation

All criminal prosecution branches in provincial jurisdictions and of Justice Canada.

All adult correctional services in Canada.

Counts of adults and youth in custody of provincial, territorial and federal correctional services.

unit of observation24
Unit of Observation

All provincial and territorial youth correctional services.

All Alternative Measures cases for youth in Canada.

All cases in maintenance enforcement programs.

All residential agencies serving women victims of family violence.

unit of observation25
Unit of Observation
  • With the exception of the UCRS and the Homicide Survey, for which the confidential data are now in Research Data Centres, the information released for all of these surveys are statistics.
  • Aggregate data consist of statistics organized in a data structure where the unit of observation is time, geography, a grouping variable, such as crime category, or a combination of these.
unit of observation26
Unit of Observation
  • The CANSIM table in Exercise #19 used time as the unit of observation.
unit of observation27
Unit of Observation

Geography can serve as the unit of observation.

This table is from the CCJS series on the DLI FTP site (file crimemun.ivt)

unit of observation28
Unit of Observation

Here categories of offences serve as the unit of observation.

This is the same table from the CCJS series as the previous slide but reshaped.

unit of observation29
Unit of Observation
  • This leaves us with the microdata from the population surveys on victimization.
  • Since 1988, the General Social Survey has conducted a victimization survey of the non-institutionalized Canadian population 15 years old and older.
  • These data are found in Cycles 3 (1988), 8 (1993), 13 (1999) and 18 (2004).
general social survey
General Social Survey
  • Two data files representing separate units of observation are provided in GSS Cycles 13 and 18. One file is structured around persons, while the other file is built around victimization incidents (excluding incidents of stalking, spousal or ex-spousal violence).
  • In Cycle 18, the person file contains 23,766 individuals and the incident file has 9,824 victimization incidents.
general social survey31
General Social Survey
  • Each of the public use microdata files has weight variables to permit generalizations to individuals and households (in the case of the main file) or types of incidents (in the case of the incident file).
  • The person file has two weights:
    • WGHT_PER : used for person-level estimates
    • WGHT_HSD : used to estimate the number of households with a given characteristic
general social survey32
General Social Survey
  • The incident file:
    • WGHT_VIC : used to estimate the number of victimization incidents in the population
    • WGHT_VIC * NUMINC : used to estimate the total number of incidents (known as series reports) with a given characteristic
    • ADJWTVIC : used to adjust for series reports with large numbers, which might otherwise lead to an inflated estimate of a type of incident
general social survey33
General Social Survey
  • Three publications to review prior to working with GSS 18:
    • “Criminal Victimization in Canada, 2004”, Juristat Vol. 25 (7)
    • General Social Survey on Victimization, Cycle 18: Personal safety and perceptions of the criminal justice system (85-566-X)
    • General Social Survey on Victimization, Cycle 18: An overview of findings (85-565-X)