Chapter 5 - Criminal Justice and Criminology Research Methods, 2nd Edition

Research Design and Measurement Chapter 5 1 Best Ways to Select Topics Personal experience. Curiosity based on something in the media. The state of knowledge in the field. Solving a problem. Personal values. Everyday life. 2 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 5 Suggestions for Constructing a Measure Remember the conceptual definition Keep an open mind. Borrow from others. Anticipate difficulties. Do not forget your units of analysis. 4 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 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 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 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 Levels of Measurement {5C22544A-7EE6-4342-B048-85BDC9FD1C3A} Different Categories Rank Order Measured Differences True Zero Nominal X Ordinal X X Interval X X X Ratio X X X X 9 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 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 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