Reliability

• The term reliability in psychological research refers to the consistency of a research study or measuring test.
• There are two types of reliability; internal and external reliability.
• Internal reliability assesses the consistency of results across items within a test.
• External reliability refers to the extent to which a measure varies from one use to another.
• Split-half reliability (internal) is done by comparing the results of one half of a test with the results from the other half.
• Split-half reliability (internal) measures the extent to which all parts of the test contribute equally to what is being measured.
• A test can be split in half in several ways, e.g. first half and second half, or by odd and even numbers. If the two halves of the test provide similar results this would suggest that the test has internal reliability.
• Test-retest and inter-rater are types of external reliability.
• The test-retest method assesses the external consistency of a test.
• Inter-rater reliability can also be called inter-observer reliability when used in observational research.
• Inter-rater refers to the degree to which different raters give consistent estimates of the same behaviour.
• The test-retest method assesses the reliability of a test by measuring the consistency of scores when the same test is administered to the same individuals at two different points in time.
• External reliability refers to the consistency of results across different settings or populations, while internal reliability refers to the consistency of results within the same study or measurement.
• External reliability refers to the consistency of research findings across different settings or populations, while internal reliability refers to the consistency of measurements within a single study.
• Reliability in psychological research refers to the consistency and stability of measurement, ensuring that the same results would be obtained if the study were repeated.
• The purpose of the test-retest method is to assess the consistency or stability of a measurement over time by administering the same test to the same group of individuals on two separate occasions.
• Inter-rater reliability in psychological research refers to the consistency or agreement between different raters or observers when assessing or coding the same behaviour.
• Test-retest measures the stability of a test over time.
• A reliable test gives similar results in similar circumstances.
• Having high reliability through standardised procedures or controls makes replication easier.