Your participation in any research study is voluntary. For every study in which you intend to participate, you will receive a document called "Informed Consent" that explains the study in straightforward language. It will state who is conducting the study, the purpose of the study, and what your involvement in the study will be. It will clearly state if there are any risks to participating and what is being done to minimize those risks. It will also describe the benefits that you may receive from participating. The informed consent document will contain the contact information for the investigators as well as the IRB. This is an important document that you should save.
A member of the research team may discuss the research study with you, explain its details, and answer your questions. You will always be able to ask a member of the research team questions.
Reading and understanding the informed consent document is your responsibility. You may discuss it with family and friends. You will not be hurried into making a decision, and you will be asked to sign or accept the document only after you understand the nature of the study and agree to the commitment.
At any time after signing the informed consent document, you are free to change your mind and decide not to participate further. This means that you are free to withdraw from the study completely, or to refuse particular treatments or tests. Sometimes, however, this will make you ineligible to continue the study. If you are no longer eligible or no longer wish to continue the study, you just need to inform the research team of your decision and you will be free to leave the study.
(Adapted from the NIH Clinical Center: http://clinicalcenter.nih.gov/participate/faqaboutcs.shtml)