Validity

What is validity?

Refers to the extent to which an observed effect is genuine

What is internal validity?

The extent to which a test measures what it is supposed to measure and effects are due to the manipulation of the IV and not some other factor e.g confounding variable.

What is external validity?

The extent to which results can be generalised beyond the study e.g other settings or other people.

What are three forms of external validity?

1. Population validity

2. Temporal validity

3. Ecological validity

What is population validity?

A form of external validity - the extent to which findings from a study can be generalised to the general population.

What is temporal validity?

A form of external validity- the extent to which findings from a study can be generalised to other particular time periods

What is ecological validity?

A form of external validity - the extent to which findings from a study can be generalised to other settings (the real world and life)

When do you have high ecological validity?

When there is realistic setting and high mundane realism

What is mundane realism?

Refers to how realistic the task in the experiment is- if an experiment has low mundane realism then the task is not similar to real life and this leads to low external validity.

What are two ways of assessing validity?

1. Face validity- independent expert looks at the measure and the extent to which test items look like what the test claims to measure

2. Concurrent validity- the extent to which a psychological measure relates to an existing similar measure. Give same group a similar, established measure and check to see if both sets of scores are positively correlated

Define face validity:

When an independent expert looks at the measure being used and assesses whether it will measure what it has set out to measure.

Define concurrent validity:

Comparing the new procedure with a similar procedure that has been done before, where validity has already been established.

List three ways to improve validity in research experiments :

1. Use a control group

2. Standardised procedures

3. Use of single and double blind procedures

List two ways to improve validity in observations:

1. Minimal input from the observer

2. Ensure behavioural categories are not too broad, overlapping or ambiguous.

List two ways to improve validity in questionnaires:

1. Include a lie scale

2. Ensure all ptpts responses are anonymous

List two ways to improve validity in qualitative methods:

1. Research may have to demonstrate the interpretive validity - researchers interpretation of events matches those of their ptpts

2. Triangulation - use of numbers of different sources as evidence