Ch4_Psychological_Measurement &Understanding Psychological Measurement .pptx

Psychological Measurement

1. Psychological Measurement Ch. 4

2. 19. Understanding Psychological Measurement Learning Objectives Define measurement and give several examples of measurement in psychology. Explain what a psychological construct is and give several examples. Distinguish conceptual from operational definitions, give examples of each, and create simple operational definitions. Distinguish the four levels of measurement, give examples of each, and explain why this distinction is important.

3. Measurement “the assignment of scores to individuals so that the scores represent some characteristic of the individuals” Examples Using a scale to “measure” one’s weight Using a thermometer to “measure” the internal temperature of a turkey roasting In Psychology, we can also refer to measurement as Psychometrics Using a test to “measure” one’s working memory capacity

4. What Do We Measure in Psychology? Constructs: variables we want to measure that are seemingly not straightforward or simple to measure i.e., A concept we are trying to measure Must use a conceptual definition Describes the behavior and internal processes that make up that construct, along with how it relates to other variables

5. How Do We Measure It? Must use the operational definition A definition of the variable in terms of precisely how it will be measured Types Self-report measure Behavioral measures Physiological measures

6. Levels (or Scales) of Measurement A variable can be measured on one of four scales: Nominal Ordinal Interval Ratio Important : Determines the type of statistics you can do and conclusions you can make

7. Scales of Measurement for Qualitative Data

8. Scales of Measurement for Quantitative Data

9. Scales of Measurement Flow Chart Does the scale involve categories or numbers? Category Can the Categories be ordered? Numbers Does the scale have a true zero point (absence of variable)? Yes Ordinal No Nominal Yes Ratio No Interval

10. Examples- Question 1 If I wanted to see which table students are more likely to approach at an organizational fair (labeled Table 1, Table 2 & Table 3), what type of scale would this be?

11. Examples- Question 2 If I wanted to see which table students are more likely to approach at an organizational fair (the 1st from the right, 2nd, or 3rd), what type of scale would this be?

12. Examples- Question 3 What is Academic Position? What about Income?

13. Examples- Question 4 Happiness Rating (1-7)? # of people that reported each value?

14. Examples- Question 5 Shirt Color? SAT Score? Range from 400- 1600

15. 20. Reliability and Validity of Measurement Learning Objectives Define reliability, including the different types and how they are assessed. Define validity, including the different types and how they are assessed. Describe the kinds of evidence that would be relevant to assessing the reliability and validity of a particular measure.

16. Reliability vs. Validity Reliability : Ability to obtain consistent scores Validity: Ability of a test to measure what it’s supposed to High Accuracy, Low Precision Low Accuracy, High Precision

17. Accuracy vs. Precision Neither Valid Reliable Valid & Reliable

18. Types of Reliability & Validity Reliability Validity Over time : Ability of a measure to be consistent across multiple administrations Test-retest Across items (internal): Ability of the same test to be consistent throughout Split-half Across different researchers: Ability for different people to measure the same test consistently Inter-rater Face Validity: How accurate something looks on the surface Content (Internal): The extent to which your test accurately/actually measures the behavior you are trying to measure (conceptual definition) Criterion Validity: Extent to which scores on a measure correlate with other related variables (as they should) Predictive or concurrent validity Convergent validity Discriminant Extent to which scores on a measure DO NOT correlate with other UNrelated variables

19. Describe Reliability and Validity Scenario #1: The Morris Shoe-Size Intelligence Test IQ = shoe size x 10 Scenario #2: You have 15 s to write as many t’s as you can Discuss the techniques you used to perform this task Now, I’ll give you another 15s to repeat the task Bolt, M. Instructor resources for Psychology retrieved from http://bcs.worthpublishers.com/WebPub/Psychology/myers11e/irm_pdf/myers11e_irm_ch10.pdf

20. 21. Practical Strategies for Psychological Measurement Learning Objectives Specify the four broad steps in the measurement process. Explain how you would decide whether to use an existing measure or create your own. Describe multiple strategies to identify and locate existing measures of psychological constructs. Describe several general principles for creating new measures and for implementing existing and new measures. Create a simple plan for assessing the reliability and validity of an existing or new measure.

21. Steps in the Measurement Process Conceptually define the Construct Decide on Operational Definition Using an existing measure Creating your own measure Implementing the Measure Caution: Look out for socially desirable responding and demand characteristics Evaluating the Measure