Background Non-responders to postal questionnaires are an important consideration for research trials, since missing data can lead to non-response bias and undermine validity of research findings. Consequently, various methods have been proposed to optimise responses rates. This paper provides results of a simple and cost-effective method that has been used in a national occupational health trial, the Skin Care Intervention in Nurses (SCIN) trial, to increase return of study questionnaires in nurses.

Methods The SCIN trial employed a range of data collection tools, including questionnaires at t = 0, t = 1 month and t = 12 months plus hand/wrists photographs. The intermediate questionnaire administered at t = 1 month was posted to participants along with a free reply envelope. After two weeks an email reminder was sent to the participants who had not returned their questionnaire. The email reinforced the importance of the trial and the need to collect data from participants. After a further two weeks non-responders were sent another hard copy of the questionnaire. Six weeks after posting the initial questionnaires we sent text message reminder to non-responders or telephoned them to remind them to complete the questionnaire.

Results The response rates in the two groups of nurse participants were as follows:

Student Nurses

Returned after 0 reminders = 46 (6%)

Returned after 1 reminder = 223 (31%)

Returned after 2 reminders = 324 (44%)

Returned after 3 reminders = 422 (58%)

Intensive Care Unit Nurses

Returned after 0 reminders = 100 (10%)

Returned after 1 reminder = 309 (31%)

Returned after 2 reminders = 473 (47%)

Returned after 3 reminders = 618 (62%)

Conclusion Use of a variety of contact mediums as reminders, resulted in a progressive improvement in the response rates to the study questionnaires. Whilst many studies only send one or two reminders to non-responders, we found that a third reminder by text/telephone improved the response rate.