This may reduce the chance that participants refuse participation for fear of ending up in a control group with an inferior treatment.
Letters include self-addressed stamped envelopes with standard refusal postcards allowing potential participants to refuse participation.
At inclusion, individuals may refuse participation (become non-participants), a potential source of bias.
First, our nurse sample might not be entirely random because potential participants could refuse participation.
Men were more likely to refuse participation than women did (refusals: male N = 177 (58.8%), female N = 124 (41.2%))(p < 0.01).
Participants with a chronic disease at baseline were more likely to refuse participation in the follow-up survey, however, participants with cancer were more likely to respond.
Participants had the right to refuse participation or terminate their involvement at any point during the study.
However, there were significant racial differences amongst those who refused participation, whereby Indians tended to refuse participation (64.2%) and Malays tended to participate (60.6%), p value = 0.036.
The participants were informed that they could refuse participation and withdraw from the study at any time, for any reason, and their informed consent was obtained.
All study participants were informed of their right to refuse participation and to leave the interview at any time.
Women may be more likely to refuse participation in a study which requires a high participant burden[ 20].
