Informed consent may be impracticable or meaningless in some research, such as research on crowd behaviour, or where fully informed consent would compromise the objectives of the research. Deception (ie research that deceives or purposely misleads or misinforms the participants about the nature of the research) and covert research should only be used when no other approach is possible, where it is crucial to the research objectives and design, or where overt observation may alter the phenomenon being studied. Researchers should also ensure, wherever necessary, they have received the relevant permission from gatekeepers to undertake the research.

The broad principle should be that covert or deceptive research should not be undertaken lightly or routinely. It is only justified if important issues are being addressed and if matters of social and/or scientific significance are likely to be discovered which cannot be uncovered in other ways. Social scientists should, wherever possible, ensure that research participants are aware of and consent to arrangements made with regard to the management and security of data, the preservation of anonymity, and any risk that may arise during or beyond the project itself, and how these might be minimised or avoided.

Any departure from a consent approach should be fully justified and, where appropriate, a protocol developed for full debriefing of participants about the true aims and objectives of the research, and participants should be given the opportunity to withdraw their data from the study (eg in experimental studies involving deception). This principle also requires that research staff be made fully aware of the proposed research and its potential risks to them and to participants.