A reputable polling organization protects its reputation by adhering to certain standards of professionalism. The most reliable polls are conducted by organizations that stick to the most exacting standards of scientific polling methodology. They will always report the information that follows. The most basic premise of survey research is that since it's just not possible to ask everybody, the next best thing is to ask a group that represents everybody. Professional polling organizations use scientific techniques to select such representative groups, or samples, randomly, a process that minimizes the possible error in the poll.
Public opinion can be quite sensitive to immediate events.
For instance, a phenomenon well known to survey professionals is the tendency of presidential approval ratings to rise immediately after a State of the Union address. As anyone who has ever tried to negotiate with a parent knows, the answer you get very often depends on the way you ask the question. Survey professionals devote a great deal of time and study to formulating polling questions that will take the true measure of public opinion by not influencing the responses of survey participants. Still, some questions will always be better than others, and it is up to you, the analyst, to determine what a poll is really saying. For this reason, it is essential to have the exact wording of any survey question and to consider it carefully.