CRIM 430

1. CRIM 430 Lecture 7 Creating Measures for Data Collection

2. The Basis of Creating Measures • Conceptual definition: Result of conceptualization—a working definition specifically assigned to a term • Operational definition: Definition that clarifies exactly how the concept will be measured—most be specific and unambiguous • Use the operational definition to conduct measurements in the real world • These are decisions that you must make based on the literature and your expertise • Creating measures or variables=Process of assigning numbers or labels to units of analysis in order to represent conceptual properties • Once your variables are defined, use them to capture observations. Those observations, in turn, are scored to allow for analysis

3. Levels of Measurement • Nominal Measures • Variables only used to capture exhaustiveness and exclusiveness (no order to responses) • Examples: Gender, race, city of residence • Ordinal Measures • Each attribute represents more or less of the variable • Examples: Sentence type, crime seriousness, fear of crime, opinion of police • Interval Measures • Rank ordered attributes and the distance between attributes has meaning and is measurable • Examples: Temperature, age, years sentenced to prison • Ratio Measures • Rank ordered attributes; distance is measurable; attributes are based on a zero starting point • Example: Amount of fine imposed

4. Types of Measures

5. Single Item Measures • Single items involve one question to capture the data you need • Single items are best used to capture demographic information, such as gender, or information that is straightforward in nature • Single items are limited in their ability to represent more complex concepts—for example, single items are not appropriate to capture an attitude toward “x”

6. Composite Measures • Single measures do not necessarily have high reliability and validity when the concept is more complex in nature • Happiness, fear of crime, child abuse, attitudes and opinions • Composite measures improve upon single item measures by using multiple items to measure one variable • Types of composite measures include: • Typologies • Indexes

7. Typologies • Typologies=Intersection of two or more aspects of the concept(s) you are trying to measure • Example 1: Court experience • Two issues: • Did you serve on a jury? • Did you testify as a witness? • Which of the following best describes your past court experience? • No experience with court • Experience as juror only • Experience as a witness only • Experience as juror and witness

8. Typologies, Continued • Example 2: The research question requires that we measure whether a respondent was a victim of sexual assault and/or a victim of domestic violence • You can ask two different items: • Have you ever been a victim of sexual assault? • Have you ever been a victim of domestic violence? • Or you can combine responses into one item: • Have you ever been a victim of sexual assault and/or domestic violence? • Not a victim of either sexual assault or domestic violence • Victim of sexual assault • Victim of domestic violence • Victim of sexual assault and domestic violence

9. Index Measures • Index: Multiple measures are created based on various aspects of the desired variable/concept • In this case, the variable you are trying to measure has many different characteristics or aspects. • These types of measures are used to increase the accuracy of measuring an attitude, perception, opinion by asking a variety of items related to the desired concept. • Together, the responses are considered a reflection of the concept, attitude, perception, or belief.

10. Index Example #1 • Example: Perception of disorder • Two dimensions required to adequately measure the concept: Extent and frequency of the problem • Two sets of questions: • To what extent do you think graffiti is a problem in your neighborhood? • Loitering is a serious problem • Loitering is a somewhat serious problem • Loitering is a little bit of a problem • Loitering is not a problem at all • How often do you see graffiti in your neighborhood? • All of the time • Some of the time • Rarely • None of the time

11. Index Example #2 • For example: Delinquency • Instead of using one item such as, “Have you ever committed delinquency?” you would provide a list of characteristics and use them collectively (a sum) to measure delinquency • Have you done any of the following in the past __?

12. Index Example #3 • Example: Self-Control • Please read each of the following items and indicate the extent to which you agree with each item. • I will often say whatever comes into my head without thinking first. • Strongly agree • Somewhat agree • Neither agree or disagree • Somewhat disagree • Strongly disagree • I enjoy working problems slowly and carefully. • Often, I don’t spend enough time thinking over a situation before I act. • Responses are summed to create a score that relates to high or low levels of self-control.

13. Assessing the Quality of Your Measures • Reliability—Will your measure, if applied repeatedly to the same object, yield the same result each time? • Test-retest—same person takes test at two different times • Interrater—two people the code same information • Validity—Are you measuring what you say you are measuring? • Face validity—common agreement • Content validity—degree to which it covers the range of meanings • Criterion-related validity—extent to which it matches outcomes of a similar, but different measure