Recently, media outlets have started including in their sampling, particularly in response to the habits of younger americans.

The answer is cellphones, Media outlets have started including cellphones in their samples, particularly in response to the habits of younger Americans.  In addition to concurrent United States government, a sample of 600 randomly carefully chosen individuals is typically precise to 5% points and the accurateness of the population sample used for the public opinion polls rest on randomness of selection, size of sample and difference in the population.