What is reliability?
How consistent the finding from an investigation or measuring device are
What is a measuring device reliable?
Produces consistent results every time it is used
What is test-retest reliability?
Method of assessing reliability of questionnaire or psychological test by testing same person on two separate occasions
What does a test-retest reliability show?
The extent the test produces the same answer
What is inter-observer reliability?
The extent of which two or more observers agree on an observation of behaviour
How is inter-observer reliability measured?
Correlating the observations of two or more observers
How do you calculate inter-observer reliability?
(Total number of agreements)/(total number of observation)
What does the calculated inter-observer reliability have to be greater than in order to have a high inter-observer reliability?
0.8
How do you improve the reliability of questionnaires?
- Should produce a correlation that exceeds +0.8
What happens if test-retest is low in questionnaires?
Some items may need to be deselected or rewritten
How do you improve the reliability of interviews?
- If not all should be trained the same
What can reduce interviewer bias?
Structured interviews as behaviours are more controlled by fixed questions
How do you improve the reliability of experiments?
How do you improve the reliability of observations?
-Making sure to have operationalised behavioural categories (measurable and self-evident)
Should categories overlap or not?
They shouldn’t