definition of reliability and validity in research

Reliability is used to mean the extent to which the measurement tool provides consistent outcomes if the measurement is repeatedly performed. Construct Validity: Construct validity in a measure refers to the extent to which it adheres to estimated correlations with other theoretical suppositions.The criterion should be relevant, unbiased, reliable, etc. whether it performs as expected or estimated, with respect to the other variables, chosen as a meaningful parameter. Criterion Validity: The type of validity which gauges the performance of measuring instrument, i.e.Content Validity: Otherwise known as face validity, it is the point to which the scale provides adequate coverage of the subject being tested.There are three types of validity, which are: To be considered as perfectly valid, it should not possess any measurement error. Simply, it measures the point to which differences discovered with the scale reflect true differences, among objects on the characteristics under study, instead of a systematic and random error. It is the most important yardstick that signals the degree to which research instrument gauges, what it is supposed to measure. In statistics, the term validity implies utility. Reliability refers to the degree to which scale produces consistent results, when repeated measurements are made.Ī reliable instrument need not be a valid instrument. Validity implies the extent to which the research instrument measures, what it is intended to measure. This article will break down the fundamental differences between validity and reliability. Validity is all about the genuineness of the research, whereas reliability is nothing but the repeatability of the outcomes. These are certain preferred qualities which gauge the goodness in measuring the characteristics under consideration.

For the purpose of checking the accuracy and applicability, a multi-item measurement scale needs to be evaluated, in terms of reliability, validity, and generalizability.

Definition of reliability and validity in research