Confidentiality of Research Data
"A major set of concerns about confidentiality pertains to the methods used to ensure that information obtained by researchers about their subjects is not improperly divulged.… It is in the interest of researchers and essential to the conduct of research on sensitive topics that researchers be able to offer subjects some assurance of confidentiality. These assurances should be given honestly, which sometimes requires the researcher and the IRB to make explicit provisions for preventing breaches of confidentiality.
In most research, assuring confidentiality is only a matter of following some routine practices: substituting codes for identifiers, removing face sheets (containing such items as names and addresses) from survey instruments containing data, properly disposing of computer sheets and other papers, limiting access to identified data, impressing on the research staff the importance of confidentiality, and storing research records in locked cabinets.… More elaborate procedures may be needed in some studies, either to give subjects the confidence they need to participate and answer questions honestly, or to enable researchers to offer strong, truthful assurances of confidentiality. Such elaborate procedures may be particularly necessary for studies in which data are collected on sensitive matters such as sexual behavior or criminal activities.…
Where data are being collected about sensitive issues (such as illegal behavior, alcohol or drug use, or sexual practices or preferences) protection of confidentiality consists of more than preventing accidental disclosures. There have been instances where the identities of subjects or research data about particular subjects have been sought by law enforcement agencies, sometimes under subpoena, and with the threat of incarceration of the uncooperative researcher. Under federal law (and some state laws), researchers can obtain an advance grant of confidentiality that will provide protection even against a subpoena for research data [Public Health Service Act §301(d)].…" [Source: http://ohrp.osophs.dhhs.gov/irb/irb_chapter3.htm]
Your best means of convincing the IRB that you will provide confidentiality of research data is by describing exactly the procedures you will use to ensure confidentiality. You should provide a similar explanation as part of your informed consent procedure.