An experiment in privacy protection.

During investigation of toxic shock syndrome in New South Wales, record keepers were requested not to disclose the identities of subjects. Nevertheless, many record keepers disclosed these identities to the investigator. Covering letters giving extra stress to privacy protection had no special effect. The extent of disclosure appeared to be greater for record keepers who either are infrequently approached for research data or lack the facilities to prepare non-identified abstracts of personal information. These record keepers may benefit from education about their responsibilities.