Greg DePersio has 13+ years of professional experience in sales and SEO and 3+ years as a writer and editor. Robert Kelly is managing director of XTS Energy LLC, and has more than three decades of ...

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 ...

The first video in Pew Research Center’s Methods 101 series helps explain random sampling – a concept that lies at the heart of all probability-based survey research – and why it’s important. Fresh ...

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 ...

Issaquah Salmon Hatchery is a facility where salmon larvae hatch and travel to the ocean, then come back as adults to repeat ...