Collect identifying information only if it is pertinent to your research question. As an example, a subject’s age would obviously be pertinent if you were researching generational attitudes toward homosexuality, but her job title and the ages of her children would probably be irrelevant. Limiting the amount and type of information you gather will make it easier to maintain the study participants' privacy and may also help to put them at ease.
Create survey forms with detachable face sheets for collecting personal data. Remove the face sheets after survey completion and store them separately. If you must retain an ability to link subjects with their responses, assign a numerical code to each survey and respondent. Restrict access to the code key to authorized personnel.
Modify identifying data so they can’t be connected to an individual respondent. This usually entails converting specific data points to general ones. For example, you might convert the respondent’s age or year of birth to an age range, his city to a region and his personal income to an income level.
Store all sensitive files in locked rooms or file cabinets. Provide access only to authorized individuals with training in privacy procedures. Ask all parties who work with, store or handle these data to sign a confidentiality agreement.
Store all sensitive digital files in an encrypted format, if possible, and protect them with passwords and a firewall. Control outside access to the data by creating a short-term account for each authorized researcher and deleting the account as soon as the researcher finishes working with the files. Change the passwords on all permanent accounts quarterly.
Store extremely sensitive physical files in a restricted location and require each authorized user to sign into and out of research sessions. For additional security, supervise the researcher's use of the files and review her notes at the end of the session.
Set and follow strict guidelines for destroying papers and digital files. Cross-shred paper files on-site instead of dumping them in a recycling bin, and permanently overwrite digital files with specialized deletion software instead of dragging them into your computer’s trash folder.