What Makes a Study Both Reliable and Valid?

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What makes a study both reliable and valid? Reliability is defined as the quality of a test such that it is consistent. It is whether a test measures something consistently. There are four different types of reliability; test-retest, parallel forms, internal consistency, and interrater. Test-rest reliability is used when you want to examine if a text is reliable over time. Parallel forms reliability is used when you want to examine the equivalence or similarity between different forms of the same test. Internal consistency reliability is used when you want to know whether the items on a test are consistent with one another in that they represent one area of interest. Interrater reliability is the measurement that tells you how much two raters agree on their judgments of some outcome. There are a few ways to ensure a test is reliable. Always make sure test instructions are clear and delete unclear items. Minimize the effects of external events, and increase the number of observations or items. Also, never make a test that is too easy or too difficult. A test is considered valid when it measures the way it says it does. Content validity, construct validity, and criterion validity are the three types of validity. Content validity measures how well a test samples a universe of items. Construct validity examines how well a test reflects an underlying construct or idea behind a test or measurement tool. How well a test reflects some criterion that occurs in either present or future is criterion validity. Criterion validity is separated into two types; concurrent (present) and predictive (future). The test and tools used to collect data must be reliable and valid, if not then the test results will be considered
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