Psych 217 Measurements-Ch. 5 PDF

Summary

This document discusses operational definitions, reliability, and validity in measurements, specifically in the context of psychology. It covers various aspects of these concepts with examples. The text details different types of reliability, validity, and how they are evaluated.

Full Transcript

**[Quality of operational definition-ch.5 measurements]** The quality of an operational definition depends on validity and reliability. [Reliability:] Evaluation of **consistency** in an experiment's results. \*\*if an experiment is not reliable then validity is not even an issue (priority is re...

**[Quality of operational definition-ch.5 measurements]** The quality of an operational definition depends on validity and reliability. [Reliability:] Evaluation of **consistency** in an experiment's results. \*\*if an experiment is not reliable then validity is not even an issue (priority is reliability) \*\*reliabiltiy is r\~ + 0.80 How to evaluate reliability: a. [Test-retest:] Try testing and retesting the experiment to see if you receive the same results. b. [Inter-rater:] Having multiple observers complete the experiment and collect data to ensure all receive same results. This avoids any bias. c. [Internal consistency:] Similarity in results of two common/related constructs. (Ex: one who suffers depression reports low on energy and happiness) Construct = concept [True score:] [Error of measurement: ] Every measurement has an evaluated error that need to be included in calculations. Classical test theory: Phenomena in which a p's obtained score is a summation of their true score and error of measurement. Obtained score = True score + Error of Measurement [Validity:] Ensuring the accuracy of measurements. Are our measurements measuring what actually intended? Forms of validity: 1. Construct validity: concept accuracy 2. Internal validity: causality possible 3. External validity: generalization of findings beyond group and setting [Construct validity types:] A. Content 1. [Face:] does it look valid? 2. [Content:] does it capture all aspect of the measure? B. Behaviour 1. [Predictive:] does it predict future behaviour? 2. [Concurrent:] behave in a way expected according to construct. Theoretically relevant behaviours. C. Other constructs 3. [Convergent:] similar scores on relevant/other constructs 4. [Discriminant/divergent:] ensure not related to what it shouldn't be related to. (Not related to unrelated construct) ![](media/image8.png)In a risking questionnaire which are correct? 1. Predictive validity = predicts future, conceptually related theories Ex: over the next 2 years 2. Convergent validity = related to scores of similar constructs Ex: self-reported extroversion and self-confidence 3. Concurrent validity = able to distinguish between theoretically relevant behaviors Ex: measure of psychopathy 4. Discriminant validity = not related to what it shouldn't be related to. Ex: jump on bridge and scream at those who did it Concurrent validity= the ability to distinguish two conceptually related behaviours (not necessarily similar), not constructs. Discriminant validity= no correlation between two unrelated constructs. Psychopathy measures have no correlation with risk taking as they shouldn't!

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