I wouldn't use שיטת הכפל הסמויה for double blinded. It's the method that is blinded. Single blind studies are those in which the subjects do not know to which group each of them is allocated while in double blind studies (please use מחקר כפול סמיות) both parties do not know the allocation of subjects to the different study groups.

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Note added at 32 mins (2009-05-26 07:11:08 GMT)
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some links:
http://www.naturemed.co.il/article/article_11.html
http://www.e-med.co.il/emed/new/usersite/content.asp?CatID=1...