Reliability and Validity
Reliable Tests Give Consistent Results
Reliability refers to how consistent or dependable a test is. A reliable test carried out in the same circumstances, on the same participant should always give the same results. There are different types of reliability:
1. Internal reliability – different parts of the test should give consistent results. The internal reliability of a test can be assessed using the spilt-half method. This splits the test into two halves and the results from both halves should produce a high positive correlation.
2. External reliability – the test should produce consistent results regardless of when it’s used.
3. Inter-rater reliability – test should give consistent results regardless of who administers it. This can be assessed by correlating the scores that each researcher produces for each participant. A high positive correlation should be found.
Valid Tests Give Accurate Results
Validity refers to how well a test measures what it claims to.…