How To Read A Poll

Political polling plays a significant role in shaping perceptions about campaigns as well as determining how resources are allocated. It’s essential that you understand how to interpret them, especially if you are tasked with explaining them to supporters.

In this article we explain the key attributes of a poll and what they mean.

Margin of Error

The margin of error reflects the precision of a poll's results and the reliability of its methodology. It indicates the range within which the true result likely falls. For example, a poll with a 3% margin of error means the results could vary by 3 percentage points in either direction from the reported number.

Sample Size

The sample size of a poll refers to the number of completed surveys used to generate results. Generally, larger sample sizes provide more accurate results, but there’s a point of diminishing returns. Beyond a certain size, increasing the sample adds little value to the poll's overall accuracy.

Cross Tabs

Cross tabs are subsets of individuals within a survey, often broken down by demographics like age, gender, or region. While useful for targeted insights, smaller groups have a larger margin of error. This means conclusions drawn from these subsets are less precise than those from the overall sample, requiring cautious interpretation.

Field Dates

Field dates refer to when a survey was conducted. Timing is crucial because public opinion can shift quickly. The longer it takes to complete a survey, the more likely conditions may change, affecting results. Polls conducted over extended periods may not capture an accurate snapshot of current sentiment.

Weighting

Weighting is a process pollsters use to adjust survey data to better reflect the demographics of the population being studied. For example, if certain age groups or regions are underrepresented, their responses may be given more influence to correct for the imbalance. While this improves accuracy, improper weighting can introduce biases, so it's essential to know how weighting was applied when interpreting poll results.

Likely vs Registered Voters

Polls often distinguish between registered voters and likely voters. Registered voter polls include anyone eligible to vote, while likely voter polls focus on those expected to cast a ballot. Determining “likely voters” may involve screening questions about voting history and interest in the election or more sophisticated modeling based on previous turnout. Since not all registered voters participate, likely voter polls can offer a more accurate prediction of election outcomes.

Methodology

Methodology refers to how a survey was conducted—whether through phone interviews, online questionnaires, or in-person polling. The method used impacts who responds and how reliable the results are. Different methods can lead to different outcomes, so understanding how the data was collected is essential for interpreting a poll’s accuracy and potential biases.

Conclusion

Understanding the fundamentals of political polling is essential for anyone working on a campaign. By familiarizing yourself with concepts like margin of error, sample size, cross tabs, and weighting, you can avoid misinterpreting data and communicate insights more effectively. Polls are valuable tools, but only when used and understood properly. With this knowledge, you’ll be better equipped to analyze polls and share accurate information with your team and supporters.