reliability definitions

what is the definition of reliability?

the consistency of a measure (if the study was to be repeated, would you get similar results)

definition of internal reliability

the consistency of results within the study (if different parts of the test measures the same thing consistently)

how can you test internal reliability?

spilt-half

how do you conduct a spilt-half test?

by comparing 2 halves of a test, if there’s high correlation then high reliability

define external reliability

will you get similar results in the same situation and same people over time

how can you test for external reliability?

inter-rater or test retest

how do you conduct inter-rater?

when you do the same test with different observers

what are the advantages of inter-rater?

• reduces bias

• data more valid

• people trust you more

what are the disadvantages of inter-rater?

• difficult to achieve similar results in subjective areas

• personal interpretations that lead to variation

how to conduct test retest

using the same test on the same participants at different occasions

what are the disadvantages of test retest?

• practice effect - improving artificially, they already know the questions

• fatigue effect - getting worse, they might be mentally drained and perform worse