Reliability and Validity - Test A or Test B?

            I would choose Test A as my preferred instrument.  Any time a test is chosen, one must consider the reliability and the validity of the instrument.  Reliability indicates how dependable, consistent, and stable the test is upon other testings (Drummond & Jones, 2006).  Validity refers to the degree to which the test measures what it is intended to measure.  This applies more to the appropriateness of the test and the interpretation of the results rather than the test itself.  It also applies to a specific group or part of a group or the purpose of the test score interpretations (Drummond & Jones, 2006).

            With test A, the reliability indicates a score of .81, indicating increasing reliability as it grows closer to the value of 1.  Test A also has a higher test, re-test ability than test B.  The scope of Test A is more narrow Test B also.  Test A appears to be more valid because it is directed to measure one specific category of a population, rather than the multiple areas that Test B is measuring.  Test A measure self-esteem alone, rather than the multiple scales of self-esteem, competence, lovability, etc. measured by Test B.  This also contributes to the higher reliability of Test A.

            More information about the population being tested would be beneficial.  Additionally, knowing the prediction errors and measurement errors of both tests could be useful also.  Knowing how the test is scored and managed would be beneficial also in knowing if the test would be good for a counselor to use with a specific group of clients.

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Reference

Drummond, R. J., & Jones, K. D. (2006). Assessment procedures for counselors and helping professionals. Upper Saddle River, NJ: Pearson/Merrill Prentice Hall.