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 ...

Low statistical power undermines the purpose of scientific research; it reduces the chance of detecting a true effect. Perhaps less intuitively, low power also reduces the likelihood that a ...

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 ...

Jason Fernando is a professional investor and writer who enjoys tackling and communicating complex business and financial problems. Erika Rasure is globally-recognized as a leading consumer economics ...