Trauma centres were invited using a standardised open letter sent by email.
Trial participation is invited using a highly secure automated online mail management system.
The study population of children ranging in age from 3 to 5 years was invited using a three-stage stratified sampling in Kashgar, the westernmost city in China.
Parents were invited using an information letter and were asked to fill in the questionnaire and the consent form.
After 1900 individuals had been invited using the recruitment process detailed above, a second invitation was sent out to give the non-responders another chance to participate and to increase the response rate.
Trial participation is invited using Docmail (http://www.cfhdocmail.com/, n.d)., a highly secure online mail management system approved by the ethics committee.
The first group of locums were invited using purposeful sampling and the second by a local association of locums.
In addition, to increase the sample size, from August 2007 to March 2008, pregnant women living in six prefectures on Kyushu Island other than Fukuoka Prefecture, with a total population of approximately 8.22 million, were invited using these documents at 252 obstetric hospitals.
Users can also share recipes they've "liked" via Facebook, as well as create "events" on Facebook, to which friends can be invited, using the menus assembled from Foodily searches.
Initially, participants from two universities were invited using their official emails.
