Researchers should inform participants of their right to refuse to participate or withdraw from research. There should be no coercion or undue influence of research participants to take part in the research
Research participants, however, may be given small monetary reimbursement for their time and expenses involved. Payment should not override the principles of freely given and fully informed consent. Participants should know before they start the research that they can withdraw from the study without losing their payment. Where monetary compensation is considered, researchers should check whether the payment constitutes taxable income and if it therefore could affect participants' welfare benefits. The responsibility lies with the researcher to check how this applies to the particular country where the research is conducted and to keep up to date with policy changes.
In some instances it may be justifiable to use techniques such as a free prize draw or book or gift vouchers to encourage survey responses. Respondents should not be required to do anything other than agree to participate or return a questionnaire to be eligible to enter a free prize draw. It should be clear that participants can enter the prize draw even if they do not answer the questions in the survey. Incentives should not be offered that require the respondent to spend money or which undermine other ethics considerations (such as anonymisation). The Market Research Society has published useful Regulations for administering incentives and free prize draws. Where children are involved, it may be appropriate to acknowledge their help with personal gifts, for example gift vouchers or gifts to participating schools. Incentives may be permissible, but anything that implies coercion (eg where an individual is compelled to participate in a study that they consider to be against their values or principles as a result of financial payments) is not.