Reliability and Validity

Question 1

What is reliability?

Answer 1

> Scientists need their results to be reliable in order for them to be considered valid
Results are reliable if they are consistent; this means that a test gives the same results each time
It is the best way to test reliability of an experiment is to repeat it.
- If the same results are obtained then the experiment is reliable

Question 2

Name two methods of testing reliability

Answer 2

Test-Retest method

Split-half method

Question 3

What is a limitation of the Test-Retest method of testing reliability

Answer 3

> Open questions and unstructured interviews lack reliability because they are difficult to replicate

Question 4

What is Split-half method of testing reliability

Answer 4

Taking half of a sample of questionnaire answers and comparing them to the other half to check reliability – (or, even numbered vs. odd numbered questions)
A significant positive correlation between the two responses would indicate reliability

Question 5

What is inner-observer reliability?

Answer 5

> The problem with making observations, especially of behaviour, is that observers can interpret the same event differently

Question 6

How can we avoid issues with inner-observer reliability?

Answer 6

More than one observer often necessary
- However, rates of reliability between
them (should be at least 85%) can differ
> Ensuring consistency between observers findings

Question 7

How can inner-observer reliability be assessed?

Answer 7

> Observer reliability can be assessed by measuring the extent to which different observers achieve similar results when observing and scoring the same participants

Question 8

How can Inner-observer reliability be improved? (2 methods)

Answer 8

• All observers should be trained
  thoroughly in the techniques they’re
  required to used prior to the data collection.
• Operational definitions should be fully
  understood

Question 9

How do we know a test is valid?

Answer 9

> A test is valid if it measures what it has been designed to measure

Question 10

Give an example of validity, (using manufacturing rulers)

Answer 10

> For example: if a manufacturer had printed the scale on a ruler incorrectly we would think we were measuring validity, but we’re not – therefore the test is not valid

Question 11

What are the two types of validity?

Answer 11

Internal and External

Question 12

What is Internal Validity?

Answer 12

Shows there is a casual relationship between the independent variable and the dependent variable in an experiment

Question 13

What is External Validity?

Answer 13

Shows the results of an experiment can be generalised to other times and places

Question 14

What are the two types of external validity?

Answer 14

Population and Ecological Validity

Question 15

What is population validity?

Answer 15

do the findings apply to target population (inc. appropriate sample)

Question 16

What is ecological validity?

Answer 16

Do findings generalise to other situations:

o E.g. lab studies = low ecological validity (false situations) but high reliability

Question 17

What are the 3 ways of measuring validity?

Answer 17

Face, concurrent, predictive validity

Question 18

What is Face validity?

measure of validity

Answer 18

simplest method of testing validity. It involves looking at the test and seeing if it looks as if it’s measuring what it’s supposed to be

Question 19

What is Concurrent validity?

measure of validity

Answer 19

uses comparisons to existing results. If a past experiment that measures the same variable is known to be valid, a new test can be compared to it

Question 20

What is predictive validity?

measure of validity

Answer 20

requires that a test can be used to make accurate predictions about future results, before it can be considered valid

Question 21

Define reliability

Answer 21

This refers to how consistent a study or measuring device is. A measurement is said to be reliable or consistent if the measurement can produce similar results if used again in similar circumstances.

Question 22

What is context validity?

External validity

Answer 22

This refers to the extent to which research finding can be generalised to settings other than that of the original research. Psychologists often call this ‘ecological validity’. It is sometimes assumed to beam applicable to everyday life, implying that this means ‘naturalistic.’ However, ecological validity more accurately means more applicable applicable across different contexts whatever these may be.

Question 23

What is temporal validity?

external validity

Answer 23

This is concerned with the ‘shelf life’ of research findings and whether they are able to endure over time

Question 24

What is Population validity?

external validity

Answer 24

This refers to the extent to which research findings can be generalised to people other than those actually involved in the actual research.