What is meant by the reliability of measurement and describe three methods for measuring reliability

What will be an ideal response?

Reliability refers to the consistency of the measurements. A measurement procedure is reliable if the same individuals measured under the same conditions produce the same (or very similar) scores. Reliability can be established over time by using test-retest reliability. The same group of individuals is measured under the same conditions at two different times. If the two measurements are the same or similar, the measurement is reliable. You can also establish the internal consistency of a test or questionnaire consisting of several items by measuring split-half reliability. The full set of items is divided in half and a separate score is computed for each half. If the two scores agree, the measurement is reliable. Finally, it is possible to demonstrate the reliability of measurement with inter-rater reliability. Two separate individuals observe and record behavior simultaneously. If their two recordings agree, the measurement is reliable.