Ch. 5 - Measurement Concepts

Question 1

What is the primary criteria that researchers use to evaluate the quality of their own and others’ research?

Answer 1

Reliability and validity

Question 2

Reliability

Answer 2

• Refers to the CONSISTENCY or stability of a measure of behaviour
• Increasing the reliability of a measure reduces uncertainty or error associated with that measure

Question 3

True score

Answer 3

-Is the person’s real score on the variable

Question 4

Measurement error

Answer 4

-The degree to which a measurement deviates from the true score value

Question 5

Pearson product-moment correlation coefficient

Answer 5

• Symbolized as “r”
• The Pearson correlation coefficient can range from 0.00 to +1.00 and 0.00 to -1.00.
• A correlation of 0 tells us that the two variables are not related at all
• The closer a correlation is to either +1 or -1, the stronger is the relationship
• The positive and negative signs provide information about the direction of the relationship

Question 6

Test-retest reliability

Answer 6

• Is assessed by giving many people the same measure twice
• A reliability coefficient determined by the correlation between scores on a measure given at one time with scores on the same measure given at a later time

Question 7

Alternate forms reliability

Answer 7

• Is sometimes used to avoid artificially high correlation coefficients if people taking the test a second time, remember it from the first time
• Alternate forms reliability involves administering two different forms of the same test to the same people at two points in time

Question 8

Internal consistency reliability

Answer 8

• Assesses how well a certain set of items relate to each other
• One common indicator of internal consistency is a value called Cronbach’s alpha

Question 9

Cronbach’s alpha

Answer 9

-An indicator of internal consistency reliability assessed by examining the average correlation of each item (question) in a measure with every other question

Question 10

Interrater reliability

Answer 10

• Is the extent to which raters agree in their observations

- A commonly used indicator of interrater reliability is called Cohen’s kappa

Question 11

Construct validity

Answer 11

-The degree to which a measurement device accurately measures the theoretical construct it is designed to measure

Question 12

Indicators of construct validity?

Answer 12

1. Face validity
2. Content validity
3. Predictive validity
4. Concurrent validity
5. Convergent validity
6. Discriminant validity

Question 13

Face validity

Answer 13

• The content of the measure appears to reflect the construct being measured
• Face validity is not sufficient to conclude that a measure has construct validity

Question 14

Content validity

Answer 14

• Is based on comparing the content of the measure with the theoretical definition of the construct
• The content of the measure captures all the necessary aspects of the construct and nothing more

Question 15

Predictive validity

Answer 15

-The construct validity is assessed by examining the ability of the measure to predict a future behaviour

Question 16

Concurrent validity

Answer 16

-Is assessed by research that examines the relationship between the measure and a criterion behaviour at the same time (ie. concurrently)

Question 17

Convergent validity

Answer 17

-Is the extent to which scores on the target measure in a question are related to scores on other measures of the same construct or similar constructs

Question 18

Discriminant validity

Answer 18

-When the measure is not related to variables with which it should not be related, discriminant validity is demonstrated

Question 19

Reactivity

Answer 19

• A problem of measurement in which the measure changes the behaviour being observed
• Awareness of being measured changes an individual’s behaviour

Question 20

What are the 4 measurement scales that a variables levels can be conceptualized in terms of?

Answer 20

1. Nominal
2. Ordinal
3. Interval
4. Ratio

Question 21

Nominal scale

Answer 21

• Categories with no numeric scales or quantitative properties
• Are sometimes called “categorical variables”
• ex. males/females, experimental condition/control condition, major of undergraduates
• Even if you were to assign numbers to the different categories, the numbers would be meaningless, except for identification
• Impossible to define any quantitative values and/or differences between/across categories

Question 22

Ordinal scale

Answer 22

• Rank ordering
• Numeric values have limited meaning
• Instead of having categories that are simply different, as in a nominal scale, the categories can be ordered from first to last
• ex. 2,3,and 4 star restaurants, birth order
• No particular value is attached to the intervals between the numbers used in ordinal scales

Question 23

Interval scale

Answer 23

• Numeric properties are literal
• Assume equal interval between values
• ex. intelligence, temperature
• No true zero, the zero on any interval scale is only an arbitrary reference point

Question 24

Ratio scale

Answer 24

• Does have an absolute zero point that indicates absence of variable measured
• Assume equal interval between values
• ex. reaction time, age, frequencies of behaviour
• Can form ratios, ex. someone responds twice as fast as another person