short read | Aug 6, 2018

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.

report | Jul 5, 2018

How Does Pew Research Center Measure the Religious Composition of the U.S.? Answers to Frequently Asked Questions

Question 1: Measuring religious identity How does Pew Research Center measure the religious identity of survey respondents and the religious composition of the U.S.? Answer: Generally, we rely on respondents’ self-identification.  A key question we ask in many surveys is: “What is your present religion, if any? Are you Protestant, Roman Catholic, Mormon, Orthodox such […]

report | Jan 26, 2018

For Weighting Online Opt-In Samples, What Matters Most?

A growing share of polling is conducted with online opt-in, or nonprobability, samples. This trend has raised some concern within the industry because, while low participation rates pose a challenge for all surveys, the online opt-in variety face additional hurdles.

fact sheet | Nov 20, 2017

Facts on Foreign Students in the U.S.

The U.S. has more foreign students enrolled in its colleges and universities than any other country in the world. Explore data about foreign students in the U.S. higher education system.

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