Foundations of Quantitative Measurement

Question 1

What is quantitative research ?

Answer 1

All variables can be converted to numeric form and analyzed using statistics. Quantitative–> quantity

Question 2

What is qualitative research?

Answer 2

More exploratory and focuses on non-numerical data

Question 3

Classical Test Theory

Answer 3

Observed score = true score + error. Can underpin the concept of reliability and validity

Question 4

Psychological Construct

Answer 4

A psychological concept that is not directly observable. It is not an object in the world;it does not have tangible existence outside of a person’s mind. (e.g. anger)

Question 5

Operational definition

Answer 5

A clear, measurable definition of a construct based on a theory. It may capture only a portion of the entire construct.

“Anger –> a specific constellation of facial muscle movement cross-culturally found”

Question 6

Measure

Answer 6

A way of observing or testing a construct.

Depression - Beck Depression Inventory Score
Motivation - number of button presses to receive reinforcement

Question 7

What is Validity –> Construct Validity (UMBRELLA TERM FOR ALL VALIDITY)

Answer 7

Construct validity refers to how well you translated or transformed a concept, idea, or behaviour - that is a construct - into a functioning and operating reality, the operationalization

Question 8

Content Validity

Answer 8

Assesses whether the measure adequately covers the different aspects of the construct that are specified in its definition. E.g. does a self-report measure of depression scale have items that capture the components of lowered mood, decreased motivation, etc.?

Question 9

Face Validity

Answer 9

Assesses whether the measure looks right on the face of it, that it self-evidently measures what it claims to measure.

The extent to which a measure “appears” to measure the underlying construct.

E.g. some personality disordered symptoms may have poor face validity due to the developmental changes in their lives.

Question 10

Criterion Validity and 2 subtypes

Answer 10

How well does the measure correlate with established “gold standard” measures of the same construct.

Concurrent validity: “At the same time –> correlate questionnaire with a clinical interview”

Predictive validity: “Predicting the future, e.g. does your measure predict future weight loss?”

Question 11

Sensitivity

Answer 11

How well a measure picks out someone who actually has the disorder (few false negatives)

Question 12

Specificity

Answer 12

How well a measure avoids diagnosing healthy people with a disorder (few false positives)

Question 13

ROC Curve

Answer 13

LARGER values on the y axis indicate better sensitivity.

SMALLER values on the x axis indicate better specificity

Question 14

Convergent Validity

Answer 14

How well the construct correlates with other measures that it should be related to (e.g. self report and clinical diagnosis of an eating disorder)

Question 15

Discriminant Validity

Answer 15

How well does a measure not correlate with measures that it should not be related to (e.g. schizophrenia symptoms and eating disorder should not be strongly related)

Question 16

Reliability

Answer 16

Refers to the degree of reproducibility of the measurement.

E.g. if you repeat the measurement in various ways, do you get the same results each time?

Question 17

Test-retest reliability

Answer 17

The measure is administered over two or more separate occasions among participants (key in longitudinal studies). More appropriate to assess personality over time compared to fear.

Question 18

Internal Consistency

Answer 18

Assessing the inter0item reliability of a sale that is composed of multiple similar items. Used to assess a questionnaire with multiple items. Do all of the items in the questionnaire measure the same thing?

Question 19

Chronbach’s Alpha

Answer 19

Used to assess internal consistency among items in a given measurement. In order to increase a, one must either increase the items of measurements, or remove items that are weakly correlated with the other items.

Question 20

Inter-rater reliability

Answer 20

It is the extent to which coders’ ratings agree or vary with each other.

Used for observation rather than self-report measures in order to check the reliability of observations.

Question 21

Nominal scales: Inter-rater reliability

Answer 21

% agreement of rating which were identical across ratings.

Can also use ordinal, ratio, or interval scales to test this.

Question 22

How to know if a construct/measure is reliable or valid based on statistics?

Answer 22

Reliability: 0.80 (good), 0.50 (poor)

Validity: 0.50 (good), poor (0.10)

Question 23

Descriptive Hypothesis

Answer 23

What is X like?

“Schizophrenia will occur very rarely in the general population”

Question 24

Descriptive/Comparison Hypothesis

Answer 24

Does group 1 differ from group 2?

“Alcoholics with have more relationship problems than non-alcoholics”

Question 25

Correlation Hypothesis

Answer 25

Do X and Y covary?

Psychopathy will be positively correlated with criminal behaviour

Question 26

Psychometric Hypothesis

Answer 26

Is a measurement reliable and valid?

The Beck Depression scale will be a reliable and valid measure of depression

Question 27

3 Most Common Hypothesis in Published Psychology Research

Answer 27

Mediation: X leads to M (mediator) which in turn leads to Y. (Perfectionism leads to increases in interpersonal conflict (mediator), which in turn predicts depression (DV).

Moderation: The relationship between X and Y varies depending on the value of the moderator, M (e.g. the relationship between stress (IV) and depression (DV) depends on an existing vulnerability(M). Specifically, stress only leads to depression in the presence of low social support)

Incremental validity: x1 predicts Y over and above another known predictor x2 (e.g. Enhancement motives will predict future binge drinking over and above past drinking)

Question 28

R2

Answer 28

The percentage that the circle overlaps is what this statistic refers to (accounting for frequency or variability)