In 2001, the Department of Defense Funded an Ongoing Study

Multiple Choice

In 2001, the Department of Defense funded an ongoing study of current and former service members to evaluate the long-term health effects of military service, including deployments. Almost 150,000 participants have been recruited so far and have agreed to complete one questionnaire every three years. This is an example of

A) A retrospective, case-control observational study.
B) A prospective, cohort observational study.
C) A survey.
D) A convenience sample.