This, and other articles on the site offer great examples of real world sampling issues, problems and solutions. nice addendum to theoretical methodology. (and just how much it matters!)
Live Polls And Online Polls Tell Different Stories About The Election
FiveThirtyEight generally takes an inclusive attitude towards polls. Our forecast models include polls from pollsters who use traditional methods, i.e., live interviewers. And we include surveys conducted with less tested techniques, such as interactive voice response (or ” robopolls”) and online panels.
… and on on predicting the presidency 🙂
2016 Election Forecast | FiveThirtyEight
Nate Silver’s predictions and polling data for the 2016 presidential election between Hillary Clinton and Donald Trump