Republicans widespread lack of trust in institutions like the news media which sponsors a great dea of polling led some people to not want to participate in polls This indicates a problem of a sampling error instead of reaching out to the general population the polls only reached out Democratic leaning voters and didn t recruit Republican voters b coverage error not using the right communication method to reach to all targeted population e g landline telephone are more likely to reach older people and or those who stay at home for longer time during a day c measurement error not measuring what researcher thought they were measuring i e instead of people s voting preference they were in fact measuring if people are going to vote by mail or in person d non response error not all potential voters contacted were willing to respond to the survey