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 researchers increasingly recognize that a single survey of the general public can rarely represent the views of small groups of Americans. Such surveys frequently have too few interviews with ...

It's not feasible to contact every member of the population, so only a sample, or a subset, of that population is included when conducting statistical research. The assumption is that the sample is ...

A new independent study proves for the first time in-store sampling not only has dramatic sales impact on the day of the sampling event, but also increases sales of established products and line ...

Will Kenton is an expert on the economy and investing laws and regulations. He previously held senior editorial roles at Investopedia and Kapitall Wire and holds a MA in Economics from The New School ...

Adam Hayes, Ph.D., CFA, is a financial writer with 15+ years Wall Street experience as a derivatives trader. Besides his extensive derivative trading expertise, Adam is an expert in economics and ...