How do people determine how many Christians, atheists, etc. are in a certain country?

Question

How do people determine how many Christians, atheists, etc. are in a certain country?

Answer 1

typically, random sampling is used.  there are other versions such as church statistics (but then you have to locate every single church in all of a nation - whoa!), but there are polls taken to determine this, just like any other opinion poll.

Answer 2

Most churches publish statistics about their membership. You would have to collect all these data and add them up. That would leave you with the rest iof the population, the size of which you could get from the local library. However, that number would contain many who, although not practising any specific religion, would not regard themselves as atheists.

   You could sample 1000 people and, from the results, calculate what those percentages are over the whole population. I think that you would find that few people would admit to being atheistic, in case there was "something in it".

Answer 3

Most countries have a National Census. Outside of that a large scale, well done poll would give a pretty good estimate.

Answer 4

I suspect the census in Muslim lands hides a considerable undercount of atheists.

Answer 5

well there is a national Census and the country takes a poll  to see what there Vote,Religion and Age

Answer 6

a National Census

Answer 7

I don't recall any UK census having included a question along these lines seeing as it's not relevant to the governnent.  That makes me suspicious of that suggestion.  Opinion surveys would appear the best source.

Update

<<well there is a national Census and the country takes a poll to see what there Vote,Religion and Age>>

I'm willing to stand corrected.  In which year did a UK census ask about voting (the answer is never) and religion (the answer is never, as far as I know)?