The Gallup World Poll measures factors such as well-being, employment, law and order, food and shelter, migration, personal health, financial issues, civic engagement, and communications as they pertain to world development indicators. These data can then be used by leaders in understanding national interests and concerns and to develop relationships between the indexes created and lagging economic outcomes. The poll is usually administered to 1,000 randomly selected individuals ages 15 and older in 160 counties worldwide once per year. Sometimes it is conducted on a semiannual or biennial basis, depending on the country. The poll consists of a set of core questions as well supplemental questions that are asked in some regions. It is administered via a one-hour face-to-face interview or a half-hour phone interview.