11 Personality and intelligence assessment 1: Basic concepts in measurement

Question 1

What is differential psychology (aka the individual differences approach)?

Answer 1

The division of psychology that seeks to understand and establish the psychological dimensions that apply to everyone, yet allow for differences between individuals.

Question 2

Are there any overt psychological attributes?

Answer 2

No, they’re all hidden. Shhhh…

Question 3

What is sampling?

Answer 3

The process of selecting some part (sample) of a target population in order to estimate some characteristics of interest in that population

Question 4

What is the paradox of sampling (Kaplan, 1964)?

Answer 4

Only way to know representativeness of sample is to know prevalence of depression, say, in population, but if you knew that you wouldn’t need the sample

Question 5

What is biasedness in a sample?

Answer 5

The degree of error in a sample, which can produce over- or under-estimates of population values

Question 6

What percentage of psychological tests are run on psychology students?

Answer 6

Approximately 68%.

Question 7

What is instability in a sample?

Answer 7

The degree of psychological homogeneity within members of population. Eg. In Christian societies test scores differ before and after Christmas

Question 8

What is psychological measurement?

Answer 8

The process of assigning numbers to a person in such a way that some attributes of the person are faithfully reflected by some properties of these numbers.

Question 9

What is a construct?

Answer 9

A construct is an explanatory variable that is not directly observable, such as intelligence or motivation.

Question 10

What is a nominal scale?

Answer 10

A scale on which an attribute is given an ARBITRARY numerical value, such as 0 - No; 1 - Yes

Question 11

What are dichtomous/polytomous scales?

Answer 11

Dichotomous –0 - No; 1 - Yes

Polytomous –0 - No; 1 - Yes; 2 - Maybe; 3 - Not sure

Question 12

What is an ordinal scale?

Answer 12

A scale on which an attribute is rank-ordered and a numerical value is assigned to each rank

Question 13

What characterises the distance between ranks in an ordinal scale?

Answer 13

The distances are meaningless.

Question 14

What is an un/balanced ordinal scale?

Answer 14

Balanced ordinal scale –has a neutral scale point in the middle. E.g. 1. Hate 2. Dislike 3. Neutral 4. Like 5. Love

Unbalanced ordinal scale – either has no neutral point or that point is not in the middle. E.g. 1. Abhor 2. Hate 3. Dislike 4. Don’t like much

Question 15

What kind of scale is a social distance scale?

Answer 15

Ordinal; unbalanced

Question 16

What’s the distinction between a Likert scale and a Likert-type scale?

Answer 16

Only a Likert scale has 5 points (degrees of agreement). Any other number -> Likert-type scale

Question 17

What is an interval scale?

Answer 17

A scale on which the points have equal distances but no true zero (eg. temperature). Not common in personality psychometrics.

Question 18

What is a ratio scale?

Answer 18

Ratios between numbers assigned to a person correspond to ratios between the measured attribute in that person. (Eg. reaction time)

Question 19

What are population norms (normative scores)?

Answer 19

Norms are standardised scores that are assumed to indicate the behaviour (distribution) of an attribute in a particular (normative) group or population.

Question 20

What is a T-score?

Answer 20

A standard score that sets the mean to fifty and standard deviation to ten.

Question 21

How do Cronbach and Meehl (1955) very usefully define a hypothetical construct?

Answer 21

Cronbach and Meehl (1955) define a hypothetical construct as a concept for which there is not a single observable referent, which cannot be directly observed, and for which there exist multiple referents, but none all-inclusive. For example, according to Cronbach and Meehl a fish is not a hypothetical construct because, despite variation in species and varieties of fish, there is an agreed upon definition for a fish with specific characteristics that distinguish a fish from a bird. Furthermore, a fish can be directly observed. On the other hand a hypothetical construct has no single referent; rather, hypothetical constructs consist of groups of functionally related behaviors, attitudes, processes, and experiences. Instead of seeing intelligence, love, or fear we see indicators or manifestations of what we have agreed to call intelligence, love, or fear.