Gallup interviews 1,000 U.S. adults each day regarding various political, economic, and wellbeing topics as part of Gallup Daily tracking. Gallup conducts interviews by telephone 350 days per year. The results, which encompass the Gallup-Healthways Well-Being Index, are reported in daily, weekly, and monthly averages and in Gallup.com stories.
Gallup Daily tracking methodology relies on live interviewers, dual-frame random-digit-dial sampling (which includes landline as well as cellular telephone phone sampling to reach those in cell phone-only households), and uses a multi-call design to reach respondents not contacted on the initial attempt. Gallup interviewers employ a "most recent birthday" selection method for choosing adult respondents within a household. Gallup Daily tracking includes Spanish-language interviews for Spanish-speaking respondents and interviews in Alaska and Hawaii.
The data are weighted daily by number of adults in the household and the respondents' reliance on cell phones, to adjust for any disproportion in selection probabilities. The data are then weighted to compensate for nonrandom nonresponse, using targets from the U.S. Census Bureau for age, region, gender, education, Hispanic ethnicity, and race. The resulting sample represents an estimated 95% of all U.S. households.
Data that are summarized at the state, congressional district, and Metropolitan Statistical Area (MSA) level are weighted at each of these levels twice per year (for states) or once per year (for congressional districts and MSAs) to ensure that samples are representative of these areas.
