University of Phoenix
June 21, 2012
Reliability and Validity
Many people think that reliability and validity is the same thing, but it is not. Although reliability and validity are often confused, they are both completely different concepts, yet they go hand in hand together. So what is reliability and validity?
According to "Experiment-Resourses.com" (2012), “The definition of reliability, as given in 'The Free Dictionary', is "Yielding the same or compatible results in different clinical experiments or statistical trials” (Definition of Reliability). When dealing with research and statistics, reliability is broken down into four types. The four types of reliability are Inter-rater, Test-retest, Parallel-forms, and Internal consistency. Inter-Rater Reliability
Inter-rater reliability evaluates reliability across different people using the same test. Inter-rater can be used in two different ways such as testing how similar people categorize items, and also how they score items. Observation is the best way to assess reliability. For example, two people may be asked to categorize photos of animals as being a pigs or cows. If they both classify the same photos in the same way, it would be a reliable result ("Changingminds.org", 2012). Test-Retest Reliability
Test-retest reliability evaluates reliability across time; if you give a person a test over and over again the results should be the same every time. According to "Changingminds.org" (2012), “Reliability can vary with the many factors that affect how a person responds to the test, including their mood, interruptions, time of day, etc. A good test will largely cope with such factors and give relatively little variation. An unreliable test is highly sensitive to such factors and will give widely varying results, even if the person re-takes the same test half an hour later. Generally speaking, the...