Describe measurements sociologists use to calculate prejudice.

Several quantititative methods of measuring prejudice are described at
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Sociologists love attitude surveys, last time I had any contact with them.

I searched Google under the key words "prejudice measure" to get these additional possible sources:

http://www.psy.unsw.edu.au/Users/BHippel/Articles/1997.vHSV.JESP.pdf
http://mentalhealth.about.com/cs/culturalissue1/a/bias304.htm
http://jca.sagepub.com/cgi/content/abstract/10/3/343
http://www.sparknotes.com/psychology/psych101/socialpsychology/section2.rhtml

I hope this helps a little more. Thanks for asking.