Reliability & Validity

Question 1

What does it mean to have a valid test?

Answer 1

The test measures what it intended to measure

Question 2

What does it mean to have a reliable test?

Answer 2

If the test can be repeated

Question 3

List the weaknesses of internal consistency

Answer 3

(1) dependent on the number of items

(2) the range of questions asked are too narrow

Question 4

Scores lower than 0.7

Answer 4

Cronbach’s alpha correlation scores lower than 0.7 are considered unreliable for research purposes

Question 5

Define test-retest reliability

Answer 5

The extent to which a measure is consistent overtime e.g. IQ score at 40 yrs similar to score at 41

Question 6

What does SEm mean?

Answer 6

An estimate of how much measurement error is associated with a test. There are 2 types associated with measurement error

1- systematic = when an observed value consistently deviates from the true value

2- random = is a chance difference between the observed and true values

Question 7

Why are confidence intervals (CIs) useful?

Answer 7

They allow researchers to estimate the range over which the population’s true mean score could lie given the observed score of the sample measured

Question 8

Higher reliability =

Answer 8

Lower measurement error

Question 9

Define content validity

Answer 9

Content validity evaluates how well a test covers all relevant parts of the topic, construct or behaviour

(Similar to face validity but with a theoretical basis)

Question 10

List and give examples of the 2 types of criterion validity

Answer 10

1- Concurrent validity = measures are taken at the same time e.g. IQ test followed by stats test to see if IQ relates to stats score

2- Predictive validity = if measures are taken at different times e.g. IQ at age 11 predicts GCSE scores at 16

Question 11

Define internal consistency

Answer 11

If your test has high internal consistency this indicates that all the items on your test are measuring the same thing

Question 12

Cronbach’s alpha reflects

Answer 12

The mean correlation between items in a scale and the number of items within the scale

Question 13

List weaknesses of face validity

Answer 13

The items on a measure may be easy to fake

Question 14

Define construct validity

Answer 14

When a test accurately measures what you intend it to measure according to the operationalised definition