This can be checked on when a survey is given a preliminary trial. Asking the right question. In phrasing survey questions it is very important to be very clear in your own mind what precisely it is that you want to find out and then be sure to phrase it unambiguously. In both of the most recent American censuses there was a big upsurge in the census counts of American Indians that could not be explained by birth and death statistics. Using surveys, we can only estimate the proportion of people who answer a question in a certain way and this may not reflect their actual behavior.
Some authors speak of social desirability bias .
In post-election polls, more people claim to have voted than actually did vote, and more people claim to have voted for the winning party than actually did so. Social desirability bias may not work the way you would expect. However, there was a consensus among the police, education officials and social workers etc. that hard drug response rate was greatly over-stated, and that most of these students were simply claiming to have used hard drugs to impress their peers. The data we want are the number actually using hard drugs, not the number claiming to have done so. With foresight, the study designers may well have been able to overcome this problem.