an article from YNET (the web edition of israels largest circulating newspaper) discusses a study by professor Sammy Smooha of University of Haifa. I've read his stuff, he is very professional and has a good ability to keep his politics by and large seperate from his work. Ideologically he isnt exactly a likud voter if you know what I mean. that makes these results all the more credible.
What it is is a study where executives of Israeli Arab knesset parties are surveyed and several thousand of their parties' registered voters are likewise surveyed.
The conclusions are that by a large margin, the positions of the leadership of these parties (and the politicians representing them) are far more radical and extreme than the electorate they claim to represent.
Its worth noting that only a very small percentage of Israeli Arabs (of which something like 95% are palestinian muslim) actually vote for Arab Parties. In spite of having a HIGHER voter turnout rate than Israeli Jews, only 28 percent of them vote for Arab Parties. the other 72 percent vote for Jewish parties, including in years past the National Religious Party.
Smooha suggests in a quote in this article that it should be clear that among those 72% or so voting for Jewish Parties it should be assumed that the discrepancies are significantly higher.