Note: This report was updated on Dec. 30, 2015 to reflect the January-July 2015 National Health Interview Survey estimates released on December 1, 2015. Telephone surveys face numerous challenges, but ...

Survey sampling and estimation methods form the cornerstone of modern statistical inference, underpinning research across the social, medical, and natural sciences. At their heart, these methods ...

One possible explanation for the variability in estimates across the different nonprobability samples is the range of methods that online sample vendors employ. They differ on recruitment, weighting ...

With a population of over 40 million users worldwide, a number doubling every year, the internet has become a medium with distinct business opportunities. To academic and commercial researchers, the ...

Survey work is a series of complex processes. At the outset, there is sample and questionnaire design, as well as field training. During the data collection stage, there is monitoring and remedial ...

Cochran (1977) outlines eleven steps in the planning of a survey. Good sampling methods must exist in the environment of all of these steps. These steps are (1) a statement of the survey objectives, ...

Do you know what worms and other hidden creatures are living in your soil? You might be amazed by the diversity and importance of these organisms for your garden. If you'd like to learn more about the ...