Reliability Assessment

Question	Answer
Reliability	How consistently a measurement technique measures the concept of interest under similar testing conditions.
Parallel test reliability	Consistency of measurement using alternative forms of the same instrument.
Test-retest reliability	Consistency of repeated measurement of a variable over time.
Inter-rater reliability	Consistency in how different observers score behaviors or phenomena.
Intra-rater reliability	Consistency in how the same observer scores behaviors or phenomena.
Internal consistency reliability	Items within an instrument correlate with each other and measure the same construct.
Cronbach’s alpha (α)	Statistic used to report internal consistency reliability of a scale.
Kappa Statistic	Chance-corrected measure of agreement for inter-rater reliability. Compares agreement against that which might be expected by chance.
Intraclass correlation	Ratio of between-groups variance to total variance used to measure inter-rater and test-retest reliability.

Resource summary

	Created by Donna Myers over 7 years ago