Table 1.

Methods used to contact study personnel in order of preference

Priority	Method of contact
1	Use original contact details provided by service personnel
2	Check that contact details have been entered correctly into the study database from their handwritten responses
3	If still serving personnel, contact MOD switchboard to determine if they have changed jobs and acquire updated contact details
4	If veteran, check 192.com (directory enquiries) for participant details
5	Check electoral register
6	Ask Army Personnel Centre to forward letter requesting new contact details
7	Ask DWP to forward contact details letter on our behalf to veterans who are claiming benefits
8	Search 192.com and electoral register for nearest relative and write to them requesting that they send our letter on to their relative
9	Check to see if service charities are in touch with veteran and ask them to pass on a letter from us
10	NHS tracing after PIAG approval
11	DWP tracing after DWP PIAG approval
12	Call mother