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Once you've found an instrument, you may want to assess its validity before you try to find the full text.
Many of the books in this guide, including Asher's Occupational Therapy Assessment Tools and the Directory of Unpublished Experimental Mental Measures, include validity and reliability information about each instrument.
You can also search the literature for reviews on the instrument you've chosen.
To find a review, you can search for the instrument name, or you can search for the instrument name and include the word review. For example, in CINAHL: