To the Editor: Survey data are difficult to publish when response rates fall below 60%. Reminder letters are the most reliable method of improving response rates in postal surveys,1,2 and three to four reminders are needed to achieve the 60% benchmark. The additional benefit of sending five or more reminders appears negligible, suggesting that four is the optimum number to maximise response rates using this approach.1

Our recent experiences suggest that human research ethics committees (HRECs) are seeking to limit the number of reminder letters on the grounds that they could be construed as harassment of research subjects. We recently submitted applications to two HRECs, seeking permission to conduct a multicentre postal survey in our local area. One committee approved the use of a single reminder letter, while the second approved the use of two. We appealed both decisions, citing evidence from earlier studies.1,2 The first committee reversed its decision and subsequently approved use of three reminders; the second committee upheld its decision to allow only two reminders. Thus, our study was effectively restricted to two reminder letters.

These experiences highlight two limitations of the ethics review process in Australia. First, the process is highly fragmented and lacks standardisation. HRECs exist as autonomous and independent entities, with varying interpretations of ethical practice. The decisions of one committee frequently undermine those of another. This is frustrating for researchers, who often have to seek permission from two or more committees during the course of a study.

Second, the process confers higher status on the rights of study participants than on the methodological demands of science. Whenever there is any actual or perceived conflict between the two, HRECs consistently rule in favour of individual rights. Researchers are reluctant to challenge the decisions of their local committee, as there is no independent review process, and appeals are usually referred back to the original committee. The result is a directive and autocratic process which fails to consider the demands of scientifically valid research.

Under current guidelines of the National Health and Medical Research Council, HRECs may endorse procedures that are potentially invasive or intrusive, provided certain conditions are met:

• the procedures are scientifically justified;

• there is no acceptable alternative; and

• reasonable steps are taken to protect individual rights.

This certainly provides scope for sanctioning four reminder letters in postal surveys.