On religious surveys...
If I am to believe that 90% of Americans "believe in God" (which I don't - I understand that we could probably shave about 20-30% off that number depending on how the surveys are phrased)...
It's difficult to do a meaningful social survey. You have to do it in a way that accounts for socio-economic differences (telephone v.s personal interview; time of day; what to do about people who don't want to participate?; etc.). The [link|http://www.norc.org/homepage.htm|National Opinion Research Center] is very good in doing meaningful surveys (e.g. if they pick you for a respondent, they'll work very hard to get you to answer their questions). They're best known for the [link|http://www.norc.org/projects/General+Social+Survey.htm|General Social Survey].
In a 2004 [link|http://chronicle.uchicago.edu/040819/protestants.shtml|story]:
The increasing secularization of American society has taken a particular toll on Protestant identity, presenting the prospect that after more than 200 years of history, the United States may soon no longer be a majority Protestant country, according to a new study by the National Opinion Research Center.
The percentage of the population that is Protestant has been falling and will likely fall below 50 percent by mid-decade or may already be there, the study showed.
Between 1972 and 1993, the Protestant share of the population remained stable, but then a decline set in. In 1993, 63 percent of Americans were Protestant, but by 2002, the number was 52 percent, the NORC research found. During the same time, the number of people who said they had no religion went up from 9 percent to nearly 14 percent. The survey listed people as Protestant if they indicated they were members of a particular Protestant denomination, such as Baptist, United Methodist or Episcopalian. Membership in many of the Protestant denominations has been declining.
[...]
Some results of the 2006 GSS are discussed by Kim at [link|http://atbozzo.blogspot.com/2007/06/science-and-religion-2006-gss.html|Tom Bozzo] and other blogs linked there. Some of the graphs are disturbing, to say the least, if you are worried about the state of basic scientific knowledge in the US. While professed religion doesn't correlate strongly with wrong answers to many questions, it does to others and the amount of education doesn't seem to matter in changing the percent correct in those cases. As a commenter on Pharyngula [link|http://scienceblogs.com/pharyngula/2007/06/lies_your_religion_told_you.php|notes]:
With a little college education, a Catholic becomes about as smart as your average unbeliever.
;-)
Another thing to keep in mind is that the answers to the questions can be contradictory:
[link|http://publicdata.norc.org:41000/gssbeta/GSSVariables_subject.html|General Social Survey (Beta)]:
Variable GODRIGHT : GOD'S LAWS SHOULD DECIDE RIGHT AND WRONG\nPreQuestion Text\nHow successful do you think the government in America is nowadays in each of the following areas?\n\nLiteral Question\nA. Right and wrong should be based on God's laws.\n\nValues \tCategories \t N \tNW\n1 \tSTRONGLY AGREE \t 358 \t365\t 28.8%\n2 \tAGREE \t 361 \t359 \t 28.3%\n3 \tNEITHER AGREE NOR DISAGREE \t269 \t277\t 21.8%\n4 \tDISAGREE \t 155 \t158\t 12.5%\n5 \tSTRONGLY DISAGREE \t 115 \t109\t 8.5%\n0 \tNAP \t49661 \t49660\n8 \tDK \t60 \t55\n9 \tNA \t41 \t38\nSummary Statistics\nValid cases \t1258\nMissing cases \t49762\nThis variable is numeric
So 57.1% Agree that Right and Wrong should be based on God's Laws (whatever they are).
Variable SOCRIGHT : SOCIETY'S LAWS SHOULD DECIDE RIGHT AND WRONG\nPreQuestion Text\nHow successful do you think the government in America is nowadays in each of the following areas?\n\nLiteral Question\nB. Right and wrong should be decided by society.\n\nValues \tCategories \t N \tNW\n1 \tSTRONGLY AGREE \t 113 \t109 \t 8.8%\n2 \tAGREE \t418 \t424 \t34.6%\n3 \tNEITHER AGREE NOR DISAGREE \t309 \t309 \t25.1%\n4 \tDISAGREE \t 241 \t238 \t19.4%\n5 \tSTRONGLY DISAGREE \t142 \t150 \t12.1%\n0 \tNAP \t49661 \t49660\n8 \tDK \t59 \t58\n9 \tNA \t77 \t72\nSummary Statistics\nValid cases \t1223\nMissing cases \t49797\nThis variable is numeric
But only 31.5% disagree when asked whether right and wrong should be decided by society.
As you note, the answers depend on how the questions are asked. ;-)
The GSS does have ~ 88% Agreement on a question asking about belief in God (Variable GODCHNGE), but the percentages are lower if you look at the questions in more detail (e.g., (Variable THEISM - which asks if God is concerned about every human being personally. Only 74% agree.).
Cheers,
Scott.