Reliability

Split-half Method

A method used to gage the reliability of a test; two sets of scores are obtained from the same test, one set from odd items and one set from even items, and the scores of the two sets are compared. If the scores are found to be similar the test is said to be internally reliable.

External Reliability

Refers to the extent to which a measure is consistent over several different occasions. External reliability of can be assessed using the test-retest method.

Internal Reliability

Refers to the extent to which a measure is consistent within itself. The internal reliability of self-report measures, such as psychometric tests and questionnaires can be assessed using the split half method.

Reliability

Reliability refers to how consistent a study or measuring device is. A measurement is said to be reliable or consistent if the measurement can produce similar results if used again in similar circumstances.

Inter-rater Reliability

The degree of agreement among raters (observers). It gives a score of how much consensus there is in the ratings given by observers. If various observers do not agree, either the scale is defective or the observers need to be re-trained.

" Test-retest method"

This method is used to assess the consistency of a test across time. Test-retest reliability is measured by administering a test at least twice at two different points in time. If the findings are consistent the test is said to have external reliability.