Table 1 Description of recruitment sources for the INTERVAL trial
Recruitment source | Source description | Invitation period | Invitation type |
|---|---|---|---|
Centre | Donors registered at a static donor centre | Jun 2012 – Jan 2013 | Letter |
Mobile (platelet) | Mobile session donors who had previously registered an interest in giving platelets at a static donor centre | Jan 2013 – Oct 2013 | Letter |
Mobile (10-mile) | Donors giving blood at a mobile session within 10 miles of a static donor centre | Jan 2013 – Oct 2013 | Letter or email |
Mobile (30-mile) | Donors with a correspondence address within 30 miles (but typically 20 miles) of a static donor centre | Jan 2013 – Oct 2013 | |
No invitation | Donors giving blood at a static donor centre who expressed an interest in joining the trial but who did not receive a previous invitation | Jun 2012 – Jun 2014 | Not applicable |