Two Emerging Issues in Epidemiologic Research

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Two Emerging Issues in Epidemiologic Research

• Access to populations for epidemiologic study
• Side effects of specialization

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Issue 1 Access to Populationsfor Epidemiologic
Study

• Often use pre-existing data
• But need primary data collection when
• No surveillance system exists
• Need exposure data not already available
• Common situation population-based case-control
  study

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• Present in 95 of U.S. households
• Used for sampling, data collection, or both
• Random digit dialing (RDD)
• Yields probability sample
• Captures unlisted phone numbers

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Number of MedLine Citations with Random digit
and Epidemiologic-methods by Year
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Now-Standard RDD Refinements

• Distribution of calls among weekday, evening,
  weekend
• Later recontacting and conversion of soft
  refusers
• High-yield sampling methods
• Mitofsky-Waksberg two-stage sampling
• List-assisted sampling

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• Are RDD response rates declining?

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Reported Participation among Controls in 69
Case-Control Studies, by Year of Publication
(Olson, 2001)
Source Am J Epidemiol 2001 154574-81
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Trend in Response Rates in CDC Behavioral Risk
Factor Surveillance System, 1994-2000
Source BRFSS 1998-9 Quality Control Reports
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Trend in Calling Effort in Behavioral Risk Factor
Surveillance System, 1995-1999
Source BRFSS 1999 Quality Control Report
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And to think if I hadnt been home having dinner
I might have missed this wonderful investment
opportunity.
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Impact of Telemarketing in the U.S.

• Employed 6 million people in 2001
• Generated 257 billion in direct sales to
  consumers in 2000
• 19 billion telemarketing dialings each month
• SUGging - Selling Under the Guise of a survey
• FRUGging - Fund Raising Under the Guise of a
  survey

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Other Contributing Factors

• More single-person households
• More households in which all adults work outside
  the home
• Answering machines
• Caller ID

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I dont know why - I just suddenly felt like
calling.
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Center for Medicare and Medicaid Services
Moratorium
As of July 2002 CMS will no longer release the
Medicare Names and Addresses file to researchers.
CMS has imposed a moratorium on the release of
this file as means for notifying beneficiaries
about research studies. We are reevaluating our
procedures to ensure that we continue to have in
place the best privacy protections for Medicare
beneficiaries.
Source www.cms.gov/data/requests/moratorium.asp,
accessed 6/5/03
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HIPAA
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Some Unfortunate Possible Responses

• Use only pre-existing data
• Use only populations of convenience
• Self-identified volunteers
• Existing samples from prior studies
• Familiar, easy-access settings workplaces, etc.
• Shift work abroad

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Some General Measures We Can Take

• Work toward more standardized reporting of study
  participation
• Promote a positive public image of epidemiologic
  research
• Feed back interesting information to participants
• Be mindful of respondent burden
• Minimize discomfort
• Scrupulously protect privacy and confidentiality

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Specific Coping Strategies1. Worry More
Selectively?

• Bias due to non-response depends on
• (a) Proportion who participate
• (b) Extent of difference between participants and
  non-participants
• Sometimes (b) is small
• But cant always predict when

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Specific Coping Strategies2. More Incremental
Improvements to RDD

• For example...
• Use answering-machine messages to distinguish
  research from telemarketing
• Increase number of call-backs
• Optimize selection and training of interviewers
• Offer incentives for participation

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The National Do Not Call Registry
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Percentage of U.S. Households with Internet
Access by Annual Household Income, 2001
Percentage of Households
Source Bureau of the Census Current Population
Survey
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Possible Future Portals of Access to Populations
1. Internet

• Useful data-collection method once study
  participation arranged
• Not (yet?) a promising successor to RDD for
  sampling

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Possible Future Portals of Access to Populations
2. Cellular Phones

• Linked more to individuals, not households
• Population coverage may become very high
• Fewer calling plans charge for incoming calls
• Text messaging or other features may permit
  initial contact without annoying interruptions

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Some Currently Available Alternatives

• Area sampling
• Lists
• Commercial mailing lists
• Drivers license records
• Voter registration lists
• Other town lists, dwelling units, etc.

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Issue 2 Side Effects of Specialization

• How epidemiologists vary
• Chronic disease / Infectious disease
• Clinical training / Non-clinical background
• Academia / Government / Industry / Other
• Basic research / Field epidemiology
• By disease or exposure area

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Side Effects of Specialization

• Fragmentation and compartmentalization
• Risk of intellectual isolation from each other

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Divisions and Interdependencies

• Chronic disease / Infectious disease
• Clinical training / Non-clinical background
• Academia / Government / Industry / Other
• Basic research / Field epidemiology
• By disease area or exposure area

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• Thank you