Wondering how many people in the United States have a smartphone? If you poll 20 people on the street, your survey won’t be representative of the entire American population. But if you just want to ...

Pew Research Center designed this study to assess the current state of online survey sampling methods – both probability-based and opt-in – and determine their accuracy on general population estimates ...

Probability-based panel: This refers to a national survey panel recruited using random sampling from a database that includes most people in the population. Today, most such panels in the United ...