title: Protecting privacy of shared epidemiologic data without compromising analysis potential.
abstract: OBJECTIVE
  Ensuring privacy of research subjects when epidemiologic data are shared with outside collaborators involves masking (modifying) the data, but overmasking can compromise utility (analysis potential). Methods of statistical disclosure control for protecting privacy may be impractical for individual researchers involved in small-scale collaborations.
  
  
  METHODS
  We investigated a simple approach based on measures of disclosure risk and analytical utility that are straightforward for epidemiologic researchers to derive. The method is illustrated using data from the Japanese Atomic-bomb Survivor population.
  
  
  RESULTS
  Masking by modest rounding did not adequately enhance security but rounding to remove several digits of relative accuracy effectively reduced the risk of identification without substantially reducing utility. Grouping or adding random noise led to noticeable bias.
  
  
  CONCLUSIONS
  When sharing epidemiologic data, it is recommended that masking be performed using rounding. Specific treatment should be determined separately in individual situations after consideration of the disclosure risks and analysis needs.
authors.affiliation: Department of Statistics, Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan. jcologne@rerf.jp
authors.forename: John
authors.initials: J
authors.lastname: Cologne
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Grant
authors.forename: Eiji
authors.initials: E
authors.lastname: Nakashima
authors.forename: Yun
authors.initials: Y
authors.lastname: Chen
authors.forename: Sachiyo
authors.initials: S
authors.lastname: Funamoto
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Katayama
mesh_terms: D003219:Confidentiality; D004307:Dose-Response Relationship, Radiation; D004781:Environmental Exposure; D004812:Epidemiologic Methods; D006801:Humans; D033181:Information Dissemination; D007564:Japan / Q000453:epidemiology; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology / Q000209:etiology; D054043:Nuclear Weapons; D012107:Research Design / Q000592:standards*; D013223:Statistics as Topic; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000209:etiology