4.5  Measuring Public  Opinion

Public opinion is measured through scientific polling, and the results of public opinion polls influence public policies and institutions. 

 Describe the elements of a scientific poll. 

Public opinion data that can impact elections and policy debates is affected by such scientific polling types and methods as:

•   Type of poll (opinion polls, benchmark or tracking polls, entrance and exit polls) 

•  Sampling techniques, identification of respondents, mass survey or focus group, sampling error

•  Type and format of questions 

Public opinion polls come in various types and help us understand what the public is thinking. They can track voting patterns and reasons behind our choices through exit polls. The measurement of our preferences influences many aspects of our lives today.

Political insights are gathered from carefully conducted public opinion polls. These polls capture the thoughts of the public at specific times. However, not all polls accurately reflect public sentiment. To assess the credibility of a public opinion poll, we must take certain precautions. Reliable polls remain neutral, use random samples, and require a large enough group to ensure validity. The margin of error is crucial as well; it indicates the possible variation in results if the poll were conducted multiple times. A margin of error of plus or minus four is generally acceptable. Additionally, the phrasing of questions plays a significant role in how polls are interpreted.

While public opinion polls can provide shortcuts in the political process, they can also be misused. For example, push polls are designed not to gauge opinions but to influence them, and they are considered unethical.

Public opinion polling is a relatively recent development in the field of science. It began with George Gallup, who conducted some initial polling for his mother-in-law, a candidate running for secretary of state in Iowa in 1932. She achieved an unexpected victory during the Democratic landslide of that year, which sparked Gallup's growing interest in politics. This early experience led to the establishment of his polling firm, which expanded across the democratic world and, in some languages, the term "Gallup" has become synonymous with opinion polling.

Collectively asking every citizen about their views on various issues would be too costly and impractical. Therefore, polls use a sample of the population, which includes a smaller group chosen to represent the larger population. Herbert Asher likens this sampling method to a blood test; just as a doctor only needs a small sample of blood to diagnose a condition, polls can accurately reflect public opinion with a relatively small group.

Typically, a random sample of about 1,000 to 1,500 individuals can reliably represent the larger pool of potential voters. The accuracy of these polls hinges on random sampling, ensuring everyone has an equal chance of being selected. This means that factors like wealth, race, age, and gender should not impact the likelihood of being chosen. If done properly, a random sample will reflect the demographics of the entire population.

It is essential to note that polling is based on estimates, and a sample can only represent the whole population with a certain level of confidence, known as sampling error. This error depends on the sample size; larger samples generally lead to higher confidence in the results. A typical survey with around 1,500 to 2,000 participants has a sampling error of ±3 percent. Thus, if 60 percent of respondents approve of the president's performance, the actual approval rate for the entire population would likely fall between 57 and 63 percent.

To achieve reliable results within this margin of error, researchers must adhere to sound sampling methods. A notable failure in polling occurred with the 1936 Literary Digest poll, which miscalculated votes for President Franklin Roosevelt by 19 percent, incorrectly forecasting a significant win for Republican Alf Landon. Despite gathering a staggering 2,376,000 responses, the magazine's flawed approach—drawing names from telephone books and motor vehicle records—skewed the results, as those sources did not represent the average American during the Great Depression. This underscores the importance of accurate representation over simply having a large number of responses. Over the last 70 years, as polling methods have improved, typical sample sizes have actually decreased rather than increased.

Advancements in computer and telephone technology have made surveying more affordable and widespread. In the past, pollsters had to rely on a large team of interviewers going door-to-door with questionnaires. Today, most polling is conducted via telephone, utilizing random-digit dialing to select samples. Pollsters make calls to randomly chosen phone numbers across the country, allowing them to reach both listed and unlisted numbers at about one-fifth of the cost of in-person interviews. However, there are some drawbacks. Approximately 2 percent of people lack a phone, and individuals are generally less inclined to participate in phone surveys compared to face-to-face interviews, as it’s easier to hang up than to turn someone away at the door. Despite these limitations, telephone polls remain an affordable option for political candidates running for lower offices, enabling them to gauge public opinion.

Nonetheless, with the rise of cell phone usage, many pollsters are concerned about the future sustainability of this method. As of 2012, studies indicated that around one in four households only had cell phone service, a figure that is notably higher among young adults and transient populations. Due to federal regulations, pollsters cannot use automated dialing for cell phones; they must manually dial numbers, which is significantly more costly. Additionally, research indicates that people are less willing to participate in surveys when contacted on a cell phone compared to a landline. Mark Mellman, a leading political pollster, estimates that gathering responses from the cell-phone-only demographic can be five to fifteen times more expensive than from landline users. While major firms like Gallup have adapted to these changes, the costs of conducting phone polls are expected to rise as more individuals disconnect their landlines.

The future of polling may increasingly rely on the Internet. Companies like Knowledge Networks create representative panels by first calling individuals to see if they would participate in online surveys. Those who agree receive small payments for their participation, and if they lack Internet access, it is provided as part of their compensation. Once enrolled, participants are contacted solely via email. This method allows for quicker and more cost-effective survey deployment, while also reducing the burden on respondents, as email notifications are less intrusive than phone calls. Many people find answering online surveys more engaging than speaking with a telephone interviewer.

From its humble beginnings with George Gallup's 1932 polls in Iowa, polling has evolved into a significant industry. Its expansion worldwide is no surprise, as there is a universal curiosity about public opinion, spanning from cities like Manhattan to Moscow and Tulsa to Tokyo.