How do news websites predict election outcomes so early?
So I understand as more people's votes are counted, it is easier to accurately predict the outcome. What I don't understand is how websites predict it with a small amount of presincts reporting in. Take yesterday's presidential election for example. Last night when West Virginia turned in 3% of their votes, cnn.com predicted (correctly) that Mitt Romney would win that state. At the time, Romney and Obama were tied at 49% each in WV. Also, how did they predict the outcome in Ohio, but not Florida. Florida has over 90% of it's votes counted, Ohio was just as close when it was predicted with under 70% turned in.
I checked Foxnews.com and npr.org and found similar results.
Reddit please teach me about statistics.
Posted Nov 7, 2012, 2:29 PM UTC
Basically for roughly 35-40 states, the outcome is known before the first ballot is cast based on demographics and historical voting data. A state like Hawaii, which 4 years ago went 70+% Obama, isn't magically going to go red this time around. Combined with exit polls, they can call a state like that with 0% reporting.