Criminal Justice and Criminology Research Methods, Second Edition Kraska / Neuman © 2012 by Pearson Higher Education, Inc Upper Saddle River, New Jersey All Rights Reserved Research Design and Measurement Chapter 5 1

Criminal Justice and Criminology Research Methods, Second Edition Kraska / Neuman © 2012 by Pearson Higher Education, Inc Upper Saddle River, New Jersey All Rights Reserved Best Ways to Select Topics 1.Personal experience. 2.Curiosity based on something in the media. 3.The state of knowledge in the field. 4.Solving a problem. 5.Personal values. 6.Everyday life. 2

Criminal Justice and Criminology Research Methods, Second Edition Kraska / Neuman © 2012 by Pearson Higher Education, Inc Upper Saddle River, New Jersey All Rights Reserved Conceptualization and Operationalization Conceptualization: The process of developing clear, rigorous, systematic conceptual definition for abstract ideas/concepts. Operationalization: The process of moving from a construct’s conceptual definition to specific activities or measure that allows a researcher to observe it empirically. Operational Definition: The definition of a variable in terms of the specific action to measure or indicate it in the empirical world. 3

Criminal Justice and Criminology Research Methods, Second Edition Kraska / Neuman © 2012 by Pearson Higher Education, Inc Upper Saddle River, New Jersey All Rights Reserved 5 Suggestions for Constructing a Measure 1.Remember the conceptual definition 2.Keep an open mind. 3.Borrow from others. 4.Anticipate difficulties. 5.Do not forget your units of analysis. 4

Criminal Justice and Criminology Research Methods, Second Edition Kraska / Neuman © 2012 by Pearson Higher Education, Inc Upper Saddle River, New Jersey All Rights Reserved Reliability and Validity Reliability: The dependability or consistency of the measure of a variable. Validity: How well an empirical indicator and the conceptual definition of the construct that the indicator is supposed to measure fit together. 5

Criminal Justice and Criminology Research Methods, Second Edition Kraska / Neuman © 2012 by Pearson Higher Education, Inc Upper Saddle River, New Jersey All Rights Reserved 3 Types of Reliability 1. Stability Reliability: Measurement reliability across time; a measure that yields consistent results at different time points, assuming what is being measured does not itself change. 2. Representative Reliability: Measurement reliability across groups; a measure that yields consistent results for various social groups. 3. Equivalence Reliability: Measurements reliability across indicators; a measure that yields consistent results using different specific indicators, assuming that all measure the same construct. 6

Criminal Justice and Criminology Research Methods, Second Edition Kraska / Neuman © 2012 by Pearson Higher Education, Inc Upper Saddle River, New Jersey All Rights Reserved 4 Types of Validity 1. Face Validity: A type of measurement validity in which an indicator makes sense as a measure of a construct in the judgment of others, especially in the scientific community. 2. Content Validity: Measurement validity that requires that a measure represent all the aspects of the conceptual definition of a construct. 3. Criterion Validity: Measurement validity that relies on some independent, outside verification. 4. Construct Validity: A type of measurement validity that uses multiple indicators of one construct converge and how well indicators of different construct diverge. 7

Criminal Justice and Criminology Research Methods, Second Edition Kraska / Neuman © 2012 by Pearson Higher Education, Inc Upper Saddle River, New Jersey All Rights Reserved Other Types of Validity 1. Concurrent Validity: Measurements validity that relies on a preexisting and already accepted measure to verify the indicator of a construct. 2. Predictive Validity: Measurement validity that relies on the occurrence of a future event or behavior that is logically consistent to verify the indicator of a construct. 3. Convergent Validity: A type of measurement validity for multiple indicators based on the idea that indicators of one construct will act alike or converge. 4. Discriminant Validity: Measurement validity for multiple indicators based on the idea that indicators of different constructs diverge. 8

Criminal Justice and Criminology Research Methods, Second Edition Kraska / Neuman © 2012 by Pearson Higher Education, Inc Upper Saddle River, New Jersey All Rights Reserved Levels of Measurement Different Categories Rank OrderMeasured Differences True Zero NominalX OrdinalXX IntervalXXX RatioXXXX 9

Criminal Justice and Criminology Research Methods, Second Edition Kraska / Neuman © 2012 by Pearson Higher Education, Inc Upper Saddle River, New Jersey All Rights Reserved Continuous and Discrete Variables Continuous Variables: Measured with an infinite number of finer gradations between variable attributes. Discrete Variables: Measured with only a limited number of distinct, separate categories. 10

Criminal Justice and Criminology Research Methods, Second Edition Kraska / Neuman © 2012 by Pearson Higher Education, Inc Upper Saddle River, New Jersey All Rights Reserved Scales and Indexes Scale: A class of quantitative data measures often used in survey research that captures the intensity, direction, level, or potency of a variable construct along a continuum. Most are at the ordinal level of measurement. Index: A measuring technique in which a researcher adds or combines numerous indicators of a construct into a single score. 11

Criminal Justice and Criminology Research Methods, Second Edition Kraska / Neuman © 2012 by Pearson Higher Education, Inc Upper Saddle River, New Jersey All Rights Reserved Likert and Thurstone Scaling Likert Scale: A scale which people express responses in terms of ordinal-level categories. Ex: Poor – Fair – Average – Good - Excellent Thurstone Scaling: A scale which the researcher gives a group of judges and asks them to rank them along a continuum and then sorts results to select items the judges agreed on. 12