Methods 101: Mode effects
How does the way a poll is conducted influence the answers people give?
How does the way a poll is conducted influence the answers people give?
Pew Research Center conducts surveys over the phone and, increasingly, online. But these two formats don’t always produce identical results.
The way polling questions are asked can influence people's answers. Survey experiments are one way to measure the degree to which different questions elicit different answers.
Detailed information on Pew Research Center international survey meethodology, such as mode of interview, sampling design, margin of error, and design effect, for each country we survey, organized by survey, country and year.
Pew Research Center uses benchmarking questions to ensure our surveys are accurate. Learn why and how we use these questions.
A new telephone survey experiment finds that an opinion poll drawn from a commercial voter file produces results similar to those from a sample based on random-digit dialing.
Many online surveys are conducted using “nonprobability” or “opt-in” samples, which are generally easier and cheaper to conduct. In our latest Methods 101 video, we explore some of the features of nonprobability surveys and how they differ from traditional probability-based polls.
Our latest Methods 101 video explores some of the ways these surveys differ from traditional probability-based polls.
An estimated 36% of U.S. public primary schools had sworn officers on site at least once a week in the 2015-16 school year, up from 21% a decade earlier.
Recent events – including the 2016 presidential election and Brexit – have rattled public confidence in polls. But this video explains why well-designed polls can still be trusted and remain an important way to measure public opinion.