Research methods - Reliability

Question 1

Define external reliability

Answer 1

the extent to which a measure is consistent when repeated. (e.g. the results of a study are consistent with an exact replication at a different time and/or with different ppts)

Question 2

define internal reliability

Answer 2

the extent to which different parts of a measure are consistent with itself. (e.g. if a 100-question IQ test is divided into two 50 questions tests, the results for each set questions with the same ppt would be similar)

Question 3

assessing internal reliability

Answer 3

split half method - e.g. tests of IQ have a large number of Q’s that test the same variable
- split the test into two parts
-participants complete both parts
- test the strength of the correlation between the two parts of the measure
- a strong correlation indicates internal reliability

Question 4

assessing external reliability

Answer 4

test-retest: repeat the study using the same procedures/measuring devices at different times and test the correlation between the two versions

inter-observer/inter-rater reliability: two (or more) observers record behaviours using the same behavioural categories test correlation

Question 5

how do you improve reliability when using experimentation

Answer 5

use standardised procedures for each ppt so they all have the same experience. e.g. keep what is said to the ppts the same (by using a script) and environmental conditions the same. Use established tests as measures rather than creating a new test.

Question 6

how do you improve reliability when using interviews and questionnaires

Answer 6

interviews: use structured interviews rather that unstructured. The interview will then include a script the interviewer can follow

questionnaires: use closed questions to reduce the range of possible responses; use established questionnaires if possible

Question 7

how do you improve reliability when using observation

Answer 7

improving the training given to observers can improve their accuracy in assigning a particular observed behaviour to the correct behavioural category. Pilot studies can identify poorly defined behavioural categories; operationalisation is the process of clearly defining a behavioural category