Are you trying to find background information about a research instrument? Or are you trying to find and obtain an actual copy of the instrument?
If you need information about a research instrument, what kind of information do you need? Do you need information on the structure of the instrument, its content, its development, its psychometric reliability or validity? What do you need?
If you plan to obtain an actual copy of the instrument to use in research, you need to be concerned not only with obtaining the instrument, but also obtaining permission to use the instrument. Research instruments may be copyrighted. To obtain permission, contact the copyright holder in writing (print or email).
If someone posts a published test or instrument without the permission of the copyright holder, they may be violating copyright and could be legally liable.
What are you trying to measure? For example, if you are studying depression, are you trying to measure the duration of depression, the intensity of depression, the change over time of the episodes, … what? The instrument must measure what you need or it is useless to you.
Factors to consider when selecting an instrument are
• Well-tested factorial structure, validity & reliability
• Availability of supportive materials and technology for entering, analyzing and interpreting results
• Availability of normative data as a reference for evaluating, interpreting, or placing in context individual test scores
• Applicable to wide range of participants
• Can also be used as personal development tool/exercise
• User-friendliness & administrative ease
• Availability; can you obtain it?
• Does it require permission from the owner to use it?
• Financial cost
• Amount of time required
Check the validity and reliability of tests and instruments. Do they really measure what they claim to measure? Do they measure consistently over time, with different research subjects and ethnic groups, and after repeated use? Research articles that used the test will often include reliability and validity data.