Glossary » informed consent
permission from a participant in a user study to participate and to have data collected about them, with that permission hinging on the fact that they have been fully informed of the nature and risks of the study and their rights in participating.
They are typically informed if their information will be confidential (usually it would be) and whether their names or images (as in videotapes) would be shown to others, such as being revealed to their management or shown to developers or in research presentations.
Their rights may include the right to withdraw from the study at any time, for instance if they are feeling distressed by it. They are also told of any compensation they will receive.