Reflection about General Social Survey CHP1
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1WhytheCJResearcherUsesStats.ppt© 2014 by Pearson Higher Education, Inc Upper Saddle River, New Jersey 07458 • All Rights Reserved
Fox/Levin/Forde, Elementary Statistics in Criminal Justice Research, 4e
Chapter 1: Why the Criminal Justice Researcher Uses Statistics
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Understand who the consumers and producers of criminal justice research are
Learning Objectives
After this lecture, you should be able to complete the following Learning Outcomes
1.1
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The Nature of Criminal Justice Research
1.1
Consumers of Criminal Justice Research
Producers of Criminal Justice Research
The General Public
Agency Administrators
Academics
Private Sector Investigators
Policymakers
Government Agencies
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Understand the core concepts and terms of criminal justice research
Learning Objectives
After this lecture, you should be able to complete the following Learning Outcomes
1.2
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1.2
- Variable – a characteristic that differs or varies from one individual to another or from one point in time to another
Ex: age, social class, attitude, unemployment, crime rate, population
- Not all characteristics vary
Constant – a characteristic that does not vary from one individual to another or from one point in time to another
- Researchers not only specify the variables they are studying, they also determine the unit of observation
Unit of observation – the element that is being studied
- ex: an individual person
Some Key Terms and Concepts
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- Sometimes researchers focus on aggregates – the way in which measures vary across entire collections of people
ex: metropolitan area
- Hypothesis – a statement of a relationship between two or more variables
Independent variable – the presumed cause
Dependent variable – the presumed effect or outcome
The variable is dependent – it’s outcome DEPENDS on the independent variable
- CJ researchers conduct research to increase their understanding of the problems and issues in their field
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Distinguish between the various forms of criminal justice research
Learning Objectives
After this lecture, you should be able to complete the following Learning Outcomes
1.3
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Forms of Research
1.3
The Experiment
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Example (Experiment)
- Levin and Thomas conducted an experiment to test the effect of racial identity of the police on perceptions of police brutality
used 3 videos which simulated a black male suspect being arrested by two LEOs
each video differed in one way: race of arresting officers
- two whites
- one black/ one white
- two blacks
- tapes were randomly shown to respondents (28 W and 33 B college students)
- respondents were asked to estimate the degree of violence and brutality employed by the arresting officers
- subjects’ perceptions of brutality were influence by the officers’ racial identity
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Forms of Research
1.3
The Quasi-Experiment
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Example: Quasi Experiment
Study of Megan’s Law: Duwe and Donnay (2008)
- can not ethically assign SO to either an experimental or a control group
- used a retrospective quasi-experimental design
compared recidivism rates of 155 high risk SO released from MN prisons (notification group) with two comparison groups
125 SO who were released prior to the imposition of Megan’s law (pre-notification)
155 lower risk SO whose location was not disclosed to the community (non-notification)
tracked recidivism rate for all groups for 8 years
- MN community notification reduces recidivism as measured by arrest, conviction and incarceration for new offenses
- not able to control for possible differences in community-based tx and in historical factors
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Forms of Research
1.3
The Survey
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Example: Survey
Palmer: relationship bt frustration and aggression
- interviewed the mothers of 51 convicted murderers
- found many more frustrating circumstances in the early lives of theses killers than in the lives of their brothers (who had not killed anyone)
- had been subject to more serious illnesses, operations, accidents, beatings, physical defects, frightening experiences, and disapproval from their peers
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Forms of Research
1.3
Meta-Analysis
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Forms of Research
1.3
Content Analysis
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Example: Content Analysis
- 2012 content analysis of substance use in 90 top grossing teen oriented films
- coded 609 characters from the films
- substance users were portrayed in a positive light
- substance use was free of conseqences
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Forms of Research
1.3
Participant Observation
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Identify the major sources of data in criminology and criminal justice
Learning Objectives
After this lecture, you should be able to complete the following Learning Outcomes
1.4
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Major Data Sources
1.4
NCVS
UCR
- National Crime Victimization Survey
- Information on crimes committed against individuals and households
- Regardless of whether the crimes were reported to the police
- Uniform Crime Reports
- Information on crimes that are reported to the police
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Understand why criminal justice researchers test hypotheses
Learning Objectives
After this lecture, you should be able to complete the following Learning Outcomes
1.5
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Why Test Hypotheses?
1.5
The acceptance of invalid conclusions
Common-sense observations are often based on narrow, biased preconceptions and personal experiences
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What do we KNOW about mass murderers?
They
- are insane
- are loners
- look different
- strangers to their victims
Research on 42 mass killers shows these to be incorrect
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Understand the stages of criminal justice research
Learning Objectives
After this lecture, you should be able to complete the following Learning Outcomes
1.6
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Interpret
and
Communicate
Results
The Stages of Criminal Justice Research
1.6
Analyze
Data
Develop
Instruments
Develop
Hypotheses
Collect
Data
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Distinguish between the three levels of measurement
Learning Objectives
After this lecture, you should be able to complete the following Learning Outcomes
1.7
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Levels of Measurement
1.7
Nominal
Ordinal
Naming or Labeling
Ordering of Categories
Interval/
Ratio
Ordering and Exact
Distances
There are different ways to measure the same variable.
- Ordinal variables can be treated as interval/ratio variables if the distances between response categories are assumed to be equal.
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Nominal Level categories are exclusive and exhaustive
- offense history (record yes/no)
- race (Asian, White, Black)
- HS grad status (yes/no)
- sex (male/ female)
- gang membership (yes/ no)
- guilt (yes/ no)
- personality type (authoritarian/ passive/ extrovert)
Ordinal level
- SES
- degree of tolerance
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Interval (and Ratio) Level
- exact distance bt categories is known
- length of prison sentence
- number of prior convictions
ratio: scores can be compared with one another and have a true zero point
- age
Ordinal data is often treated as interval
- difference is not always clear
- often choose to treat ordinal as interval
- allows for more powerful statistic tools
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Distinguish between the descriptive and decision-making functions of statistics
Learning Objectives
After this lecture, you should be able to complete the following Learning Outcomes
1.8
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The Functions of Statistics
1.8
Description
Decisions
- Frequency and grouped-frequency distributions
- Graphs and tables
- Arithmetic averages
- Inferences and generalizations from a sample to a population
- Testing hypotheses regarding the nature of social reality
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Description
- researchers quantify their data at the nominal, ordinal or interval level of measurement
- use statistics to either describe or make decisions
- Description
- researchers often study hundreds, thousands or even larger numbers
- use of grouped frequency distributions, graphs and means can help us find patterns
- statistics, in this case, may be defined as a set of techniques for the reduction of quantitative data to a small number of more convenient and easily communicated descriptive terms
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Decision Making
- can use statistics to test hypotheses and make inferences
- cost and time preclude researchers from studying an entire population
- in statistics, we use a sample of data to understand the characteristics of the population from which it was drawn
- this allows us to generalize to the larger population
- errors results from sampling (inevitable)
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Example: page 17-19
Hypothesis: Male college students are more likely than female college students to have tried MJ.
- tested at an urban university with 10,000 male and 10,000 female enrollees
- 35 out of 100 males AND 15 out of 100 females had tried MJ
- must test for statistical significance
- statistics, in this case, is a set of decision making techniques that aid researchers in drawing inferences from samples to populations and hence in testing hypotheses regarding the nature of social reality.
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An Important Note About Rounding
round a FINAL answer to two more decimal digits than contained in the original score
do not round until your FINAL answer
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© 2014 by Pearson Higher Education, Inc Upper Saddle River, New Jersey 07458 • All Rights Reserved
Consumers of criminal justice research include the general public, agency administrators, and policymakers. Producers of criminal justice research include academics, private sector investigators, and government agencies.
Variables, constants, units of observation, hypotheses, independent variables, and dependent variables are encountered regularly by criminal justice researchers.
Experiments, quasi-experiments, surveys, meta-analyses, content analyses, and participant observation are forms of research commonly used by criminal justice researchers
Much of the data used in criminal justice research comes from the NCVS and UCR.
CHAPTER SUMMARY
1.1
1.2
1.3
1.4
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© 2014 by Pearson Higher Education, Inc Upper Saddle River, New Jersey 07458 • All Rights Reserved
Criminal justice research goes through specific stages from developing hypotheses and instruments to collecting and analyzing data, and to interpreting and communicating results.
CHAPTER SUMMARY
1.5
1.6
1.7
Criminal justice researchers work with three levels of measurement: nominal, ordinal, and interval/ratio.
Statistics can be used to describe data and make decisions.
Criminal justice researchers test hypotheses to avoid the acceptance of invalid conclusions.
1.8
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