1000 people is enough to get a good estimate of opinion providing it is sampled well. Its one of the counter intuitive results of statistics that a few thousand opinions is enough to get a small percent margin of the average opinions of the sampled population no matter its size. The trouble with polling is that “average opinion of people who answer polls when asked” is not “average opinion of the group that you want to represent”, the whole art of polling is in finding the mapping between those two groups. But that isn’t helped by polling 10 or 100 thousand people instead of 1000.
There are a number of studies on the methodology of polling that suggest the margin of error is much wider than typically reported by polls by about an order of magnitude in part due to sample size. Although there are a number of non-sample size related issues, like the one you mentioned and people misreporting/lying, at play as well.
1000 people is enough to get a good estimate of opinion providing it is sampled well. Its one of the counter intuitive results of statistics that a few thousand opinions is enough to get a small percent margin of the average opinions of the sampled population no matter its size. The trouble with polling is that “average opinion of people who answer polls when asked” is not “average opinion of the group that you want to represent”, the whole art of polling is in finding the mapping between those two groups. But that isn’t helped by polling 10 or 100 thousand people instead of 1000.
There are a number of studies on the methodology of polling that suggest the margin of error is much wider than typically reported by polls by about an order of magnitude in part due to sample size. Although there are a number of non-sample size related issues, like the one you mentioned and people misreporting/lying, at play as well.