>Except in 2016 In 2016 the national polls were very close to the final result--within a couple points. Remember that Clinton won the popular vote. State poll

>Except in 2016 In 2016 the national polls were very close to the final result--within a couple points. Remember that Clinton won the popular vote. State polls were less accurate, but the general consensus is they were wrong due to undecided voters breaking more for Trump than is normal in the final few days--after the final state polls were conducted. That being said, your point stands. Sample method is generally more important than sample size, and 4,000 game devs who self selected to attend a conference is very unlikely to be a representative sample.