Session 3 : Psychometrics

Question 1

Psychological measurement

Answer 1

the assignment of scores to individuals so that the scores represent some characteristic of the individuals (some constructs are not observable)

Question 2

Four steps in the measurement process

Answer 2

• conceptually defining the construct
• operationally defining the construct
• implementing the measure
• evaluating the measure

Question 3

Conceptual definiton (conceptually defining the construct)

Answer 3

a conceptual definition of a psychological contruct describes the behaviors and internal processes that make up that construct, along with how it related to other variables

Question 4

Operational definiton (operationally defining the construct)

Answer 4

a definitions of a variable of precisely how it is to be measured

Question 5

Three categories of operational definition

Answer 5

• self-report measures
• behavioral measures
• pyhsiological measures

Question 6

Levels of measurement

Answer 6

• nominal level (assigning scores that are category levels)
• ordinal level (assigning scores that represent rank order of individuals)
• interval level (assigning scores using numerical scales in which intervals have the same interpretation throuhgout)
• ratio level (assinging scors in such way that there is a true zeor point that represents the complete absence of the quantity)

Question 7

Evaluating a measure (two distinct criteria)

Answer 7

• Reliability

- Validity

Question 8

Reliability

Answer 8

refers to the consistency of a measure across time, across items, and scorss researchers

Question 9

Validity

Answer 9

the extent to which some scores from a measure actually represent the varibale they are intended to

Question 10

Three types of reliability

Answer 10

• Test-retes reliabiliy: reliability over time
• Interrater reliability: reliability across different resaerchers
• Internal consistency: reliability across items

Question 11

Test-retest reliability

Answer 11

the extent to which the scores obtained by a measure of a construct are consistent over time

Question 12

Interrater reliability

Answer 12

the extent to which different observers are consistent in their judgements

Question 13

Internal consistency

Answer 13

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

• observed score = true score + measurement error
• all items should reflect the same underlying construct

Question 14

Internal consistency

Answer 14

can assess internal consistency by split-half correlation or Cronbach’s alpha
- greater than 0.7 (good internal consistency)

Question 15

Different kinds of validity

Answer 15

• face validity
• content validity
• criterion validity
• discriminant validity
• construct validity

Question 16

Face validity

Answer 16

face validity is the extent to which a measurement method appears on its face to measure the construct of interest (on its surface)

• assessed informally
• weak for of validity

Question 17

Content validity

Answer 17

the extent to which a measure covers the contruct of interest
- usually assessed by carefully checking the measument method against the conceptual definiiton of the construct

Question 18

Criterion validity

Answer 18

the extent to which poeple’s scores on a measure are correlated with other variables (known as criteria) that one would expect them to be correlated with

Question 19

Criteria

Answer 19

any variable that one would expect them to be correlated with

Question 20

Different options of criteria validity

Answer 20

• congruent validity (construct, criterion measured at the same time)
• predictive validity (criterion ismeasured at some point in the future)
• convergent validty (criterion is another measure of the same construct)

Question 21

Discriminant validity

Answer 21

the extent to which scores on a measure are not correlated wiht measures of variables that are conceptually distinct

Question 22

Construct validity

Answer 22

refers to wether a measure actually reflects te construct that it is supposed to measure
- most important form of validity

Question 23

nomological net

Answer 23

assesses contruct validity (does this actually reflect the construct?)

Question 24

Multi-trait, multi-method matrix

Answer 24

describes construct valdity, does this actually reflects the construct?