It is a Zionist secret: the Washington Institute does not identify the polling firms which conduct its surveys in the Middle East

"A reliable new West Bank/Gaza public opinion survey conducted on June 15-17 -- the only such poll since the current kidnapping crisis began -- shows that Palestinian popular attitudes have hardened considerably on long-term issues of peace with Israel. Commissioned by The Washington Institute and conducted by a leading Palestinian pollster".  Well, that sounds very reliable and credible indeed.