Over the past five years, Pew Research Center has conducted surveys in the United States using our American Trends Panel, a randomly selected, probability-based sample of U.S. adults ages 18 and older ...

Differences in participation rates and l... Differences in participation rates and lessons learned about recruitment of participants - The European Health Examination Survey Pilot Project This is the ...

The San Antonio hub of an international study assessing aspirin's effects in the elderly is leading all U.S. centers in number of ethnic minority recruitments.