Introduction
Test reliability is affected by several factors that can cause errors or increase reliability. Psychologists have to consider these factors during tests to ensure the tests are reliable. Furthermore, psychologists should know the difference between systematic and random errors.
Normally, psychologists carry out a test and compare the results against other results. Comparing the test results against pool of many other results of individuals who took the same test could result in errors. This is because there is no guarantee that an individual’s results would be similar to those of other people. The person could be from a different culture, age group or background from those people making up the comparison group.
Evaluator’s level of training
Psychological tests should be interpreted by an expert who is objective. Evaluators must have sufficient training to ensure they give accurate and reliable interpretations. If the level of training of the practitioner is low, there is likely to be human errors. Careless or incompetent evaluators are prone to make human errors hence reducing test reliability.
Random and systematic errors
Evaluators must understand the difference between systematic and random errors when conducting psychology tests. This would help them know where these errors are likely to arise and avoid them. Random errors arise due to environmental conditions or measuring instruments such as using inappropriate test methods. They can be corrected by conducting the test several times. Systematic errors are errors that occur at any stage of the test consistently. The errors are skewed to one side of the test because the test is obscured by a certain factor. For instance, if a weighing machine adds 2kg each time it weighs body weight, the test is corrected by subtracting 2kg each time a measurement is taken.
Conclusion
Therefore, test reliability is affected by factors such as evaluator training and competence and the standards used to measure the test. Test reliability is compromised if errors such as random and systematic errors occur. Psychologists must be keen to eliminate these errors to improve test reliability.
References
MCintire, S. A., & Miller, L. A. (2007). Foundations of psychological testing: A practical approach (2nd Edition ed.). London: Thousand Oaks CA: Sage.
Schultz, D. P., & Schultz, S. E. (2010). Psychology and Work Today. An Introduction to Industrial and Organizational Psychology. New York: Pearson Education.
