Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link
Volume 12, Number 4—April 2006

Computer-assisted Telephone Interview Techniques

On This Page
Article Metrics
citations of this article
EID Journal Metrics on Scopus

Cite This Article

To the Editor: Fox et al. used computer-assisted telephone interview (CATI) techniques in an outbreak of cryptosporidiosis (1). Australian health agencies have used CATI for several years. A case-control study during an outbreak of Salmonella Mbandaka in 1996 employed CATI to interview 15 case-patients and 45 controls; contaminated peanut butter was implicated (2). Foodborne disease outbreaks are often geographically widespread and suited to using CATI.

Australian health authorities investigate ≈100 outbreaks of foodborne disease each year, with 3–4 using CATI-based case-control studies. Some jurisdictions investigate outbreaks by using CATI interviews of controls sampled from a bank of potential study participants (3). Potential study participants are recruited at the conclusion of rolling risk factor survey interviews, similar to the Behavioral Risk Factor Surveillance System.

A "control bank" allows investigators to rapidly obtain contact details for appropriately matched controls because age and sex of all household members are recorded in a database. Using control banks with CATI allows completion of studies quicker than CATI or traditional methods alone (4). South Australia has used CATI during 11 case-control studies of salmonellosis, legionellosis, Q fever, campylobacteriosis, Shiga toxin–producing Escherichia coli, and cryptosporidiosis (

During an Australian CATI survey about gastroenteritis, 5,123 (84%) of 6,087 households agreed to be in a control bank (5). This bank of 14,024 potential controls was used in 4 case-control studies of sporadic salmonellosis and campylobacteriosis. This system avoided randomly dialing thousands of households to enroll controls in young age groups. The control bank was used for 3 years after initial collection, although many jurisdictions update banks annually.

Investigators may find CATI useful, although it can be costly and introduce biases (4). Programming questionnaires can delay investigations, which makes paper-based collection better in small outbreaks (4). CATI cannot be used in areas where a small proportion of the population has telephones. Despite limitations, CATI, when combined with control banks, may improve outbreak investigations.


Martyn Kirk*, Ingrid Tribe†, Rod Givney†, Jane Raupach†, and Russell J. Stafford‡
Author affiliations: *OzFoodNet, Canberra, Australian Capital Territory, Australia; †Communicable Disease Control Branch, Adelaide, South Australia, Australia; ‡OzFoodNet, Brisbane, Queensland, Australia



  1. Fox  LM, Ocfemia  MCB, Hunt  DC, Blackburn  BG, Neises  D, Kent  WK, Emergency survey methods in acute cryptosporidiosis outbreak. Emerg Infect Dis. 2005;11:72931.PubMedGoogle Scholar
  2. Scheil  W, Cameron  S, Dalton  C, Murray  C, Wilson  D. A South Australian Salmonella Mbandaka outbreak investigation using a database to select controls. Aust N Z J Public Health. 1998;22:5369.PubMedGoogle Scholar
  3. Kenny  B, Hall  R, Cameron  S. Consumer attitudes and behaviours—key risk factors in an outbreak of Salmonella typhimurium phage type 12 infection sourced to chicken nuggets. Aust N Z J Public Health. 1999;23:1647.PubMedGoogle Scholar
  4. Hope  K, Dalton  C, Beers Deeble  M, Unicomb  L. Biases and efficiencies associated with two different control sources in a case-control study of Salmonella typhimurium phage type 12 infection. Australas Epidemiol. 2005;12:26.
  5. Hall  G, Kirk  M, Ashbolt  R, Stafford  RJ, Lalor  K. OzFoodNet Working Group. Frequency of infectious gastrointestinal illness in Australia, 2002: regional, seasonal and demographic variation. Epidemiol Infect. 2006;134:1118.PubMedGoogle Scholar


Cite This Article

DOI: 10.3201/eid1204.050756

Related Links


In response: We appreciate the comments of Martyn Kirk and colleagues, who describe their experience using computer-assisted telephone interview (CATI) techniques in Australia with geographically widespread foodborne outbreaks (1). The intent of our article was to illustrate 1 example of the use of the CATI infrastructure in investigating a large communitywide cryptosporidiosis outbreak (2); yet we recognize the applicability of this infrastructure to multiple acute infectious disease outbreak scenarios.

In our article, we comment that the use of existing CATI systems, like the Behavioral Risk Factor Surveillance System (BRFSS), can provide a practical means for obtaining controls in case-control studies, and the letter by Kirk and colleagues describes their use of the CATI infrastructure to create a "control bank" for acute infectious disease outbreak investigations. This control bank includes participants of longitudinal risk factor surveys, like BRFSS, who are subsequently recruited as controls for outbreak investigations. We acknowledge that a "bank" of these readily accessible controls could permit more rapid recruitment of participants in numerous age strata and obviate the need for extensive random digit dialing to recruit an adequate age-matched control population in many investigations. Nevertheless, in most epidemiologic investigations, controls need to be selected from the same geographic area as the case-patients, and even in large telephone surveys, the number of respondents in any given region can be small. This would make it difficult to recruit enough controls within the small areas affected by most outbreaks, particularly within specific age strata. A control bank may therefore be more practical for use in large communitywide outbreaks, outbreaks that occur over large regions (i.e., an entire state), or in densely populated areas. Additionally, the lengthy start-up time required for questionnaire programming with a CATI system also supports the view that the CATI method may be maximally applicable in large-scale investigations.

LeAnne Fox, Division of Infectious Diseases, Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; fax: 617-730-0254
Author affiliations: *Centers for Disease Control and Prevention, Atlanta, Georgia, USA; †Kansas Department of Health and Environment, Topeka, Kansas, USA,; ‡University of Kansas Medical Center, Kansas City, Kansas, USA


  1. Kirk  M, Tribe  I, Givney  R, Raupach  J, Stafford  R. Computer-assisted telephone interview techniques. Emerg Infect Dis. 2006;12:697.PubMedGoogle Scholar
  2. Fox  LM, Ocfemia  MCB, Hunt  DC, Blackburn  BG, Neises  D, Kent  WK, Emergency survey methods in acute cryptosporidiosis outbreak. Emerg Infect Dis. 2005;11:72931.PubMedGoogle Scholar

Table of Contents – Volume 12, Number 4—April 2006


Please use the form below to submit correspondence to the authors:

Send To

10000 character(s) remaining.


Page created: January 23, 2012
Page updated: January 23, 2012
Page reviewed: January 23, 2012
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.