Lecture 2: Measurement, Distributions, Reliability & Validity

Measurement, Distributions, Reliability and Validity 9th October 2024 Dr Andrew Hodrien 1 Covering today Measurement Distributions Reliability and Validity 2 Measurement 3 Operationalisation Psycholo...

Measurement, Distributions, Reliability and Validity 9th October 2024 Dr Andrew Hodrien 1 Covering today Measurement Distributions Reliability and Validity 2 Measurement 3 Operationalisation Psychological construct measured indirectly – inferring that a measurable outcome varies with this. Measure outcome that changes as a function of the construct Can’t directly access some experiences (e.g., experience of red, joy, memories etc.) Find behavioural outcome with 4 reasonable chance of varying with Types of Measures in Psychological Science Self-report Behaviou Physiologi ral cal 5 Converging Measures Behavioura l Eviden Self- ce Physiologic report al 6 Levels of Measurement 7 Primary Scales of Measurement 8 Measurement Scales Scale Order Distanc True Examples e Zero Nominal no no no Colour, Gender, Ethnicity, Country Ordinal yes no no Rating scales, Rank orders Interval yes yes no Time of day, Year, IQ, Likert scales Ratio yes yes yes Age, Height, Weight, Rates 9 Measurement Scales Categoric al Scale Order Distanc True Examples e Zero Nominal no no no Colour, Gender, Ethnicity, Country Ordinal yes no no Rating scales, Rank orders Interval yes yes no Time of day, Year, IQ, Likert scales Ratio yes yes yes Age, Height, Weight, Rates Quantitati ve 10 Distributions 11 Distributions Avera ge Short Tall 12 Error in Distributions 13 Skewed Distributions 14 Skewed Distributions Nine Hours Sleep Normal Population Four Hours Sleep Bad Good Bad Good Bad Good Memory Memory Memory Memory Memory Memory Memory 15 Why is it so important? Group Group carryin carryin g big g no rock rock 100 200 Distance (m) 16 Reliability and Validity 17 Important Factors in Your Measure Reliability Validity 18 Types of Reliability Test-Retest Reliability Internal Consistency Reliability Inter-Rater Reliability 19 Test-Retest Reliability Week 1 Week 2 Results Results 1) 23 1) 20 2) 15 2) 14 3) 10 3) 11 4) 18 4) 20 5) 15 5) 14 20 Internal Consistency Reliability I consider myself a friendly person: 1 2 3 4 5 Not at all Very much I consider myself an amicable person: 1 2 3 4 5 Not at all Very much 21 Internal Consistency Reliability I consider myself a friendly person: 1 2 3 4 5 Not at all Very much I consider myself an amicable person: 1 2 3 4 5 Not at all Very much 22 Inter-Rater Reliability Behavioural measures – experimenter records participant outcomes No objective way so person codes this – as subjective measure need multiple coders Identify source of bias in the coder and ensure consistency 23 Types of Validity Face Validity Construct/Content Validity Criterion Validity 24 Face Validity Dream Dream Content Content Measure Measure Question: Question: Explain what How many you saw in hours sleep your dream. do you regularly have? 25 Construct/Content Validity Construct: Whether the measure covers the variable Content: Whether the measure completely covers the variable Interest in emotion affecting memory but only measure short-term memory = low validity Also look at sensory memory, long-term memory = high validity 26 Criterion Validity New Measure Established Measure Score = 10 Score = 10 27 SONA studies to participate in 28 Thank you for listening! 29