Where necessary a reminder questionnaire was sent six weeks after the first mailing.
One reminder questionnaire will be issued to non-responders before they are deemed to have withdrawn.
A final reminder questionnaire was sent to non-responders two weeks following the telephone approach.
A single reminder questionnaire was posted to non-responders after 4 6 weeks.
Non-respondents received a reminder (questionnaire and prepaid envelope) after four weeks.
722 consecutive parents were randomly allocated to receive a voucher or not with the reminder questionnaire (see Table 1).
Non-responders were sent a reminder questionnaire after 2 months and subsequently contacted by phone to encourage them to participate.
A reminder questionnaire was sent out four weeks after dispatch, if no response was obtained to the initial mailing.
MOCS will be completed in 2008 and a voucher is being sent to all parents with the reminder questionnaire.
Non-responders were sent a reminder questionnaire three weeks later and received a reminder phone call after a further three weeks.
