A new telephone survey experiment finds that, despite major structural differences, an opinion poll drawn from a commercial voter file can produce results similar to those from a sample based on ...

This study looks at how national public opinion polling in the United States changed from 2000 to 2022. It focuses on two aspects: the sample source(s) – that is, where the survey takers came from – ...

Medical research is essential for advancing the understanding of health, diseases, and treatments. There are many types of studies that serve different purposes. Medical research, or health research, ...