A data set of protected health information that excludes all of the 16 HIPAA specified direct identifiers related to an individual or of relatives, employers, or household members of the individual, but retains geographic subdivisions larger than the postal address, elements of dates including month and day as well as other unique identifying numbers, characteristics or codes not previously listed as a direct identifier and cannot reasonably be used to identify an individual. Limited data sets may only be used for research, public health or for health care operations; and only in conjunction with a data use agreement.
