Reliability

What is reliability?

Reliability means consistency — if a study or measurement is reliable, it should produce the same results every time it's repeated (under the same conditions).

What is internal reliability?

Used for: Questionnaires and tests
Looks at how consistent the items are within a test.

What is external reliability?

Refers to how consistent a measure is across time or different situations

What are the 2 methods of assessing reliability?

• Test-retest reliability

• Inter-rater reliability

What is test-retest?

Repeat the study using the same procedures/measuring devices at different times and test the correlation between the two versions

What is inter-observer reliability?

Used in observations — where two or more observers watch and record behaviour independently using the same behavioural categories; then, they test the correlation between each tally of behaviour to identify if the behavioural categories are appropriately operationalised.

How to improve reliability in lab experiments?

• Standardised procedures

• Control extraneous variables

How to improve reliability in observations?

• Use behavioural categories that are clear and operationalised

• Train observers properly

• Conduct a pilot study to refine the coding system

How to improve reliability in questionnaires?

• Use clear, unambiguous questions

• Use closed-ended or fixed response options

How to improve reliability in interviews?

• Use structured interviews with set questions

• Avoid leading or ambiguous questions

• Train the interviewer to stay consistent