As the U.S. presidential election approaches, news reports and social media feeds are increasingly filled with data from public opinion polls. How do pollsters know which candidate is ahead in what swing state or with which key demographic group? Or what issues are most important to as many as 264 million eligible voters across a vast country? As the U.S. presidential election approaches, news reports and social media feeds are increasingly filled with data from public opinion polls. How do pollsters know which candidate is ahead in what swing state or with which key demographic group? Or what issues are most important to as many as 264 million eligible voters across a vast country? Political science Phys.org – latest science and technology news stories