This defines the instrument’s consistency in measuring what it intends to measure.
How to Determine the Validity and Reliability of an Instrument Show Validity and reliability are two important factors to consider when developing and testing any instrument (e.g., content assessment test, questionnaire) for use in a study. Attention to these considerations helps to insure the quality of your measurement and of the data collected for your study. Understanding and Testing Validity Validity refers to the degree to which an instrument accurately measures what it intends to measure. Three common types of validity for researchers and evaluators to consider are content, construct, and criterion validities.
Often times, when developing, modifying, and interpreting the validity of a given instrument, rather than view or test each type of validity individually, researchers and evaluators test for evidence of several different forms of validity, collectively (e.g., see Samuel Messick’s work regarding validity). Understanding and Testing Reliability Reliability refers to the degree to which an instrument yields consistent results. Common measures of reliability include internal consistency, test-retest, and inter-rater reliabilities.
Developing a valid and reliable instrument usually requires multiple iterations of piloting and testing which can be resource intensive. Therefore, when available, I suggest using already established valid and reliable instruments, such as those published in peer-reviewed journal articles. However, even when using these instruments, you should re-check validity and reliability, using the methods of your study and your own participants’ data before running additional statistical analyses. This process will confirm that the instrument performs, as intended, in your study with the population you are studying, even though they are identical to the purpose and population for which the instrument was initially developed. Below are a few additional, useful readings to further inform your understanding of validity and reliability. Resources for Understanding and Testing Reliability
This entry was posted in Uncategorized. Bookmark the permalink. What is consistency in measurement called?Reliability refers to the consistency of a measure. Psychologists consider three types of consistency: over time (test-retest reliability), across items (internal consistency), and across different researchers (inter-rater reliability).
What is measurement consistency reliability?Reliability refers to how consistently a method measures something. If the same result can be consistently achieved by using the same methods under the same circumstances, the measurement is considered reliable.
When a test accurately measures what it is intended to measure?Validity is the extent to which a test measures what it claims to measure. It is vital for a test to be valid in order for the results to be accurately applied and interpreted.
What is the stability of the consistency of measurement?Reliability is the stability, consistency, and precision of a given measure.
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