While there is no magic length that an online survey should be, Pew Research Center caps the length of its online American Trends Panel surveys at 15 minutes.
National polls like the Center’s come within a few percentage points, on average, of benchmarks from high response rate federal surveys.
Public polling estimates on COVID-19 vaccination have been within about 2.8 points, on average, of the CDC's calculated rate.
A new evaluation of the Center's national American Trends Panel finds little evidence that panel estimates are affected by errors associated with panel conditioning, a phenomenon that occurs when survey participation changes respondents’ true or reported behavior over time.
Looking at final estimates of the outcome of the 2020 U.S. presidential race, 93% of national polls overstated the Democratic candidate’s support among voters, while nearly as many (88%) did so in 2016.
Given the errors in 2016 and 2020 election polling, how much should we trust polls that attempt to measure opinions on issues?
If a battleground state poll does not adjust for having too many college graduates, it is at risk of overstating support for a Democratic presidential candidate. The Current Population Survey provides high-quality data that can mitigate overrepresentation of college graduates.
While the growth of online interviewing is a prominent trend in polling, there is variation within that trend in how researchers recruit respondents. This study finds that sourcing affects data quality.
I wrote an introductory blog post about how to access and analyze Pew Research Center survey data with R, a free, open-source software for statistical analysis. The post showed how to perform tasks using the survey package.