Why was there a polling miss?

Polling misses occur due to a variety of factors, primarily related to sampling issues and predictive challenges:

1. Sampling Skew: Experts like Doug Rivers explain that errors usually stem from sampling biases rather than pure statistical sampling error. For instance, in the New Hampshire primary, polls overrepresented educated voters and didn't adequately correct for this skew, leading to inaccurate results 1.

2. Nonresponse Bias: Some demographics, such as Trump's strongest supporters, are less likely to respond to polls, leading to skewed data that fails to accurately reflect their voting behavior 2.

3. Turnout Models: Predicting who will actually vote is challenging. Turnout models can be incorrect, especially when unexpected groups show high or low turnout. Small errors in turnout assumptions can create significant polling inaccuracies 3 4.

   Polling Errors

   Russ Roberts

   Doug Rivers

   Discover the factors that contribute to polling errors and why they can lead to inaccurate predictions in this insightful episode.

   

   EconTalk

   Doug Rivers on Polling

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4. Shifts in Voter Behavior: Rapid changes in voter preferences or behaviors, such as a sudden surge of enthusiasm among particular groups, can be hard to capture accurately 5.

5. Technical Errors and Data Handling: Issues like data entry errors or premature calls based on exit polls, as seen in the 2000 Florida election, can also lead to significant misses 6.

The combination of these factors makes polling a complex and frequently imperfect science.