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Stony Brook University

Psychological Tests & Instruments

Provides explanations, search tips, and other advice for locating and using psychological and educational instruments.

Reliability and Validity

How do you know whether you've found a “good” or “bad” instrument? Is the instrument well-designed?

Researchers often discuss the “validity” of instruments, rather than whether they are “good” or “bad.” According to the Sage Encyclopedia of Social Science Research Methods, validity is “the extent to which any measuring instrument measures what it is intended to measure.” Validity is an important indication of whether an instrument will be useful. 

Validity and reliability information can sometimes be found in the Mental Measurements Yearbook and other resources listed in this guide.

However, as the Sage Encyclopedia also explains, validity not only depends on the instrument itself, but how you use the instrument. Even if an instrument is generally considered to be “valid,” it might not be applicable to the particular group, behavior, or situation you are trying to study (Thousand Oaks, CA: Sage Publications, 2004, p. 1171).


This book is available through SBU Libraries and can help understand the statistics used in reliability and validity studies.

Using Instruments Ethically

If you find a copy of an instrument, can you just go ahead and use it?

No. Some instruments can only be purchased, administered, or interpreted by a licensed or certified professional.

Even if you are qualified to administer the instrument, there are a lot of other things you may need to do first. These include, but are not limited to:

  1. Talking with your professor about whether the instrument is appropriate for your project
  2. Getting the author’s/publisher’s permission to use the instrument
  3. Getting any training or certification that is required to administer the instrument properly
  4. Recruiting test subjects in a proper and ethical manner
  5. Finding an appropriate environment to test them
  6. Making arrangements for storing and analyzing your data
  7. And more!!