Reliability

What is reliability?

Reliability refers to whether something is inconsistent. Researchers should be able to replicate a method time and time again and get the same or similar results.

What should psychologists do to get the same results?

Researchers should be able to replicate a method time and time again and get the same or similar results

Why is reliability important?

Reliability is important in research because we can be more confident of the conclusions.

Measuring Reliability

Test-Retest Method

What is the test-Retest Method?

The test-retest method is where the same participants take the same test twice, at different occasions. If the results from the two occasions highly correlate (with a correlation co-effecient of at least +0.8), the test is said to be reliable.

What is this method most commonly used with?

Questionnaires and psychological tests (e.g. IQ tests). There must be sufficient amount of time between test and retest to ensure the participant cannot recall their answers but not so long where the participant has significantly changed.

What should there be in the test-retest method?

There must be sufficient amount of time between test and retest to ensure the participant cannot recall their answers but not so long where the participant has significantly changed.

Inter-Observer Reliability

What is inter-observer reliability?

Inter-observer reliability is used to measure the reliability of observations. Two (or more) observers watch the same behaviours with the same behavioural categories.

What do the observers do similarly and differently?

The observers watch the same events, but record their behaviour independently. If the results from the different observers highly correlates (with a correlation co-efficient of at least +0.8), the observation team is recording behaviour reliability.

What are similar processes that can assess the reliability of interviews?

A similar process can be used to assess the reliability of interviews (inter-interviewer reliability) and content analysis (inter-rater reliability).