Psychometrics

Question 1

Why be concerned with reliability and validity?

Answer 1

• It reduces the chance of error
• It strengthens the value of findings
• It makes interpretation of data more sound
• It makes applicability of tool more valuable
• It may influence the lives of people

Question 2

Reliability

Answer 2

• consistency of a measure

- measure must be stable across time and circumstance

Question 3

Test-retest Reliability

Answer 3

consistency over time

Question 4

Internal Consistency

Answer 4

consistency of responses across the items on a multiple-item measure

Question 5

Inter-rater Reliability

Answer 5

consistency between different observers in their judgments

Question 6

Split-half Correlation

Answer 6

• This involves splitting the items into two sets, such as the first and second halves of the items or the even- and odd-numbered items.
• Then a score is computed for each set of items, and the relationship between the two sets of scores is examined.

Question 7

Crombach’s α

Answer 7

The mean of all possible split-half correlations for a set of items.

Question 8

Validity

Answer 8

whether a given measure accurately measures what it purports to measure

Question 9

Face Validity

Answer 9

• The extent to which a measurement method appears “on its face” to measure the construct
• very weak kind of evidence
• based on people’s intuitions about human behaviour
• intuition is often wrong

Question 10

Content Validity

Answer 10

The extent to which a measure “covers” the construct of interest
- assessed qualitatively against conceptual definition of the construct

Question 11

Construct Validity

Answer 11

Involves an empirical and rational examination of how well a measure or instrument reflects some theoretical construct or explanation of behavior
- “why” a test is valid

Question 12

Criterion Validity

Answer 12

The extent to which people’s scores on a measure are correlated with other variables (known as criteria) that one would expect them to be correlated with
- A criterion can be any variable that one has reason to think should be correlated with the construct being measured, and there will usually be many of them

Question 13

Concurrent Validity

Answer 13

When the criterion is measured at the same time as the construct

Question 14

Predictive Validity

Answer 14

When the criterion is measured at some point in the future (after the construct has been measured)
- The predictive validity of the first test is tied to a criterion validity of the second test

Question 15

Convergent Validity

Answer 15

Other measures of the same construct.

Question 16

Discriminant Validity

Answer 16

The extent to which scores on a measure are not correlated with measures of variables that are conceptually distinct.

Question 17

Ecological Validity

Answer 17

Driven by “common sense”; a measure that can meet reasonable expectations of a given tool.

Question 18

Utility

Answer 18

• Is the data precise and reliable, at the lowest possible cost (Efficiency)?
• Can the method be applied successfully to a wide range of phenomena (Generality)?