2.2. Survey administrationLists of personnel, including long-term contractors, were obtained from each operating nuclear power plant in the U.S., and approximately 100 individuals from each site were randomly selected to participate in the survey. The survey was administered through the internet, and e-mail invitations with a link to the survey were sent to the selected participants at each site. Senior management at each site was contacted to request that the survey be announced and participation encouraged. The survey administrator sent an average of two reminder e-mails to people who did not respond to the first invitation, until a minimum of 30 respondents from each site was obtained. Data collection began on June 14 and ended on August 11, 2010.