Population-based cohort study based on questionnaires and nationwide registries.
The study was based on questionnaires given to the children's parents.
DaEuMon is based on questionnaires and was compiled under the FP6-project EuMon9,46.
The Indiana and North Carolina exit polls were based on questionnaires completed by voters in each state's primary election.
Data for 1996 were based on a survey conducted by Voter News Service based on questionnaires with 16,627 voters.
The unit's findings are based on questionnaires completed each year by about 40,000 pupils aged 9 to 15.
The Election Day polls were based on questionnaires completed by voters leaving voting stations in six states yesterday.
The Election Day polls were based on questionnaires completed yesterday by voters leaving voting stations throughout Michigan and Arizona.
Data for 1994 were collected by Voter News Service based on questionnaires completed by 1,775 voters.
Data for 1992 were collected by Voter Research and Surveys based on questionnaires completed by 1,997 voters.
The census statistics are estimates, based on questionnaires mailed at random, but they are considered the most accurate numbers available.
