Methods 101: Mode effects
How does the way a poll is conducted influence the answers people give?
Phone vs. online surveys: Why do respondents’ answers sometimes differ by mode?
Pew Research Center conducts surveys over the phone and, increasingly, online. But these two formats don’t always produce identical results.
How highly religious Americans view evolution depends on how they’re asked about it
Evolution remains a contentious issue. When asked about it, highly religious Americans' responses can vary depending on how the question is asked.
‘Good jobs’ vs. ‘jobs’: Survey experiments can measure the effects of question wording – and more
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.
International Methodology
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.
How asking about your sleep, smoking or yoga habits can help pollsters verify their findings
Pew Research Center uses benchmarking questions to ensure our surveys are accurate. Learn why and how we use these questions.
‘Defining the universe’ is essential when writing about survey data
Given the wide range of people we speak to for our polls – and the issues we ask them about – it’s important to be as clear as possible about exactly who says what. In research circles, this practice is sometimes called “defining the universe."
Comparing Survey Sampling Strategies: Random-Digit Dial vs. Voter Files
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.
What are nonprobability surveys?
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.
Methods 101: What are nonprobability surveys?
Our latest Methods 101 video explores some of the ways these surveys differ from traditional probability-based polls.
