Research instruments fall into two categories:
Published instruments include well-known tests and measures and their reliability and validity are usually well established. They may be available
The following government databases contain information about both published and unpublished instruments.
Published instruments can be purchased from the publisher. Access is typically restricted to individuals qualified to use or administer the test. See publishers websites for more information.
Listed below are two well-known test publishers, but there are many more.
Where can you find information about unpublished research instruments?
It can be challenging to find a copy of an unpublished instrument. Sometimes you can obtain a copy by contacting the author of the test or measure. When searching databases you may occasionally find the full text of a research instrument in the appendices of an article, but typically you will only find mention of the measurement tool in the methods section.
This is a small sampling of links to measurement tools that are available online.