Error Variance and Reliability Coefficients in Testing and Assessing
In this week's readings from the Psychological Testing and Assessment text, you read about three sources of error variance that occur in testing and assessment. These include:
Test construction.
Test administration.
Test scoring and interpretation.
Additionally, other sources of error may be suspect. You were also introduced to reliability coefficients, which provide information about these sources of error variance on a test.
The following reliability coefficients were obtained from studies on a new test, THING, purporting to measure a new construct (that is, Something). Alternate forms of the test were also developed and examined in subsequent studies published in peer-reviewed journals. The alternate test forms were titled THING 1 and THING 2. (Remember to refer back to your Psychological Testing and Assessment text for information about using and interpreting a coefficient of reliability.)
Internal consistency reliability coefficient = .92
Alternate forms reliability coefficient = .82
Test-retest reliability coefficient = .50
In your post for this week:
Describe what these scores mean.
Interpret these results individually in terms of the information they provide on sources of error variance.
Synthesize all of these interpretations into a final evaluation of this test's utility or usefulness.
Explain whether these data are acceptable.
Explain under what conditions they may not be acceptable and under what conditions, if any, they may be appropriate.
APA 7th ed
Error Variance and Reliability Coefficients in Testing and Assessing ‘Something’
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Error Variance and Reliability Coefficients in Testing and Assessing ‘Something’
Error variance in testing and assessment refers to the variability in test scores caused by factors other than the measured item. Error variance can significantly affect the reliability and validity of test results and can also impact the ability to make inferences about test-takers using their scores (Baumgartner et al., 2021). Therefore, test developers, administrators, and scorers need to be aware of these sources of error variance and take steps to minimize their impact.
Three primary sources of error variance can occur in assessments. One is the test construction error variance which can occur when test items do not accurately measure the construct they are intended to measure, when the test is not correctly calibrated, or when the test is not appropriate for the population being tested. Two is the test administration error variance which can happen due to factors such as test-taker fatigue, lack of test-taker motivation, or the presence of distractions in the testing environment (Curby et al., 2020). On the other hand, test scoring and interpretation error variance can occur due to factors such as inconsistent scoring or misinterpretation of test scores. Bias in scoring or interpretation can also lead to errors in test results.
On the other hand, reliability coefficients are measures of how stable and consistent test outcomes are over time and are used to estimate how free test scores are from measurement error. There are several types of reliability coefficients, some of which include test-retest and alternate-form reliability, which compares scores from the same test given to the same group of individuals on two separate occasions, and contrasts scores from different versions of the same test consecutively (Gitomer et al., 2021). Lastly, internal consistency reliability compares scores of different items within the same test. Coefficients measure from 0 to 1, with 1 indicating perfect reliability and 0 showing no dependability. Additionally, reliability coefficients above .70 are considered acceptable.
The internal consistency reliability coefficient of .92, the alternate forms reliability coefficient of .82, and the test-retest...