[Conflicts of interest and the ethics of developing fee-charging questionnaires].

There are some fee-charged questionnaires in the social medicine field. If a questionnaire is fee-charged, the researcher developing it may have a financial incentive, and the existence of a conflict of interest should be considered. Therefore, when a manuscript reporting a fee-charged questionnaire is submitted, future fee-charging and the institution managing the questionnaire should be described as potential conflicts of interest. They should also be so described in forms for ethical review and informed consent.