Reliability and Validity and Their Importance in Research

Reliability and Validity
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Reliability and Validity
Reliability entails measuring the same thing many times and recording the outcomes under similar conditions. In other words, it refers to the consistency of a certain measure or the extent to which specific results can be reproduced if the study is repeated without altering the conditions. Additionally, validity involves using the right instrument or test to measure the thing that needs to be measured (Salkind, 2017). Indeed, it means that the outcomes obtained are measured with the right tool or test. The paper focuses on the types and importance of validity and reliability.
Since reliability is the measure of consistency for a specific instrument, it ought to be established before testing a hypothesis (Salkind, 2017). In particular, the various types of reliability include test-retest, parallel-forms, internal consistency, and inter-rater. Test-retest reliability refers to the measure of how a test is stable over time. As such, a similar test is given to a specific group of individuals at different times (Salkind, 2017). Another type of reliability is the parallel-forms. Indeed, it involves taking different forms of a similar test, which is given to the same respondents. Afterward, the score sets are correlated with one another.
Inter-rater reliability refers to the consistency of the measurement from rater to rater, instead of test to test or time to time. In other terms, it examines the consistency of measurement across raters. This type of reliability is used to determine the agreement between two raters (Salkind, 2017). Internal consistency depicts how items in an assessment or test are unified. For instance, if someone is administering a test with 50 items, each item should be related to each other based on the theory or model used. In most cases, internal consistency is usually evaluated by correlating the performance of each item in a scale or test, which might entail a correlation coefficient. Kuder-Richardson and Cronbach’s alpha are the two commonly used statistical correlation coefficients (Salkind, 2017).
Besides, distinctive types of reliability are used for different purposes. For example, test-retest reliability measures the consistency of a specific test over time. When it comes to parallel-forms reliability, it measures the consistency from form to form. Inter-rater examines the measurement consistency from rater to rater (Salkind, 2017). Regardless of the differences between the different types of reliability, the primary similarity...