Rapid Needs Assessments and GIS

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Rapid Needs Assessments and GIS
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Goals

• Describe the uses of rapid needs assessments in
  post-disaster settings
• Understand the sampling methodology used with
  rapid needs assessments
• Discuss how geographic information systems can be
  used with rapid needs assessment
• Provide examples of other types of rapid surveys
  in public health

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Rapid Needs Assessments

• Provide information about community needs in
  disaster aftermath (1)
• Provide information to match emergency needs with
  available resources
• When used with rapid mobilization of resources
  can reduce adverse public health consequences (2)

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Rapid Needs Assessments

• Rapid needs assessments can
• establish the extent/possible evolution of an
  emergency
• measure the present/potential public health
  impact
• determine existing response capacity and identify
  any additional immediate needs
• inform priority response actions (3)

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Methodology

• Accurate sampling is important
• World Health Organization Expanded Programme on
  Immunization (EPI) cluster sampling
  methodology(4)
• EPI method is a 2-stage cluster sample
• 1st stage - 30 clusters (geographical areas)
  selected
• 2nd stage - 7 points (housing units) within each
  cluster

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EPI Method

• Easy to implement in the field
• Requires few resources
• Yields reasonably valid and precise estimates

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Two-stage cluster sampling

• Has been adapted over the years for various
  purposes. (6)
• 1960s tool for local health departments to
  assess community coverage of immunization,
  service coverage
• 1970s modified and used with smallpox
  eradication in West Africa
• 1980s adapted by WHO for EPI program
• 1990s revised to include community volunteers,
  incorporate census data and random sampling of
  second-stage participants. Adapted by CDC for
  rapid needs assessments after disasters

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EPI Cluster Sampling Example

• Hurricane Andrew, Florida, 1992
• EPI cluster-sampling method used
• Clusters defined in grid of quarter-mile square
  areas using street maps of 2 communities hit
  hardest by hurricane

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Cluster samplingHurricane Andrew

• Street map of Homestead-Florida City with
  super-imposed sampling frame of quarter-mile
  square clusters used during rapid needs
  assessment after Hurricane Andrew. (6)

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Cluster SamplingHurricane Andrew

• Survey--interviews conducted at 7 housing units
  in each of 30 clusters
• Separate surveys conducted at 3, 7, and 10 days
  after hurricane landfall
• Surveys used to provide information to public
  health officials for directing and monitoring
  relief units (6)

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Modified EPI Cluster Sampling

• 1996, EPI cluster sampling method modified
• Added features included the ability to
• Estimate size of overall post-disaster population
• Estimate numbers of persons with specific needs
• Assess number of damaged/destroyed housing units

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Modified EPI Cluster Sampling

• Disaster site divided into blocks/clusters
• First stage, a sample of n clusters (n30 as in
  EPI method) such that
• Clusters with more housing units are likely to be
  included (probability proportional to estimated
  number of housing units)
• Second stage, equal probability of k housing
  units is chosen (k30 as in EPI method)
• Interview conducted at each housing unit

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Modified EPI Cluster Sampling

• Interviewer makes multiple attempts to conduct an
  interview at a selected housing unit
• EPI methodinterviewer moves to adjacent housing
  unit after single interview attempt
• If repeated attempts do not result in interview,
  a 0 is recorded for that site
• Allows for collection of more information than
  EPI method (housing units are counted, those
  damaged/destroyed are noted, all persons in
  selected households are counted)
• Data can be used to estimate size of overall
  disaster population

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Modified EPI Cluster Sampling

• Adopted by CDC as the standard for conducting
  rapid needs assessments after disasters
• First used in North Carolina after Hurricane
  Isabel in 2003

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Rapid Surveys for Community Assessments

• Rapid survey method used with post-disaster needs
  assessments can be adapted for other community
  assessments
• Example Rapid survey in Hispanic area of Los
  Angeles to look at immunization status (9)
• Example North Carolina county health departments
  conducting community health assessments and
  assessing population vulnerabilities prior to
  potential catastrophic events (10)

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Geographic Information Systems

• Geographic information systems (GIS) can be a
  useful tool for conducting rapid needs
  assessments or rapid surveys
• GIS can provide a more scientific approach to
  second stage randomization
• Random points can be selected and plotted
• Interviews are conducted with a resident of the
  house located nearest to the random point
• Reduces potential selection bias by interview
  teams

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Advantages of Using GIS

• Using GIS allows use of global positioning system
  (GPS)-based routing
• GPS
• Aids team in navigation
• Provides more up-to-date maps
• Replaces paper maps

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Advantages of Using GIS

• GIS can replace paper-based surveys with
  computer-based surveys
• GIS software can be uploaded onto handheld
  computers for field deployment
• Computer-based data entry can save time, reduce
  data entry errors

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Summary

• Rapid needs assessment is an essential component
  of disaster relief operations (6)
• Rapid needs assessments allow public health
  officials to quickly identify and prioritize
  areas of need
• Methods used with rapid needs assessment can be
  extended to other areas of public health

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References

• 1. Surveillance and rapid needs assessment.
  Centers for Disease Control and Prevention. Web
  site. http//www.cdc.gov/nceh/hsb/disaster/surveil
  lance.htm. Accessed April 24, 2008.
• 2. Lillibridge SR, Noji EK, Burkle FM. Disaster
  assessment The emergency health evaluation of a
  population affected by a disaster. Ann Emerg Med.
  1993221715-1720.
• 3. World Health Organization. Rapid health
  assessment proocols for emergencies. Geneva,
  Switzerland World Health Organization 19991.
• 4. Frerichs RR. Rapid surveys. Department of
  Epidemiology, School of Public Health, University
  of California, Los Angeles Web site.
  http//www.ph.ucla.edu/epi/rapidsurvey.html.
  Updated May 26, 2008. Accessed June 4, 2008.

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References

•  5. Lemenshow S, Robinson D. Surveys to measure
  programme coverage and impact A review of the
  methodology used by the Expanded Programme on
  Immunization. World Health Stat Q. 19853865-75.
• 6. Hlady WG, Quenemoen LE, Armenia-Cope RR et al.
  Use of a modified cluster sampling method to
  perform rapid needs assessment after Hurricane
  Andrew. Ann Emerg Med. 199423(4)719-725.
• 7. Malilay J, Flanders WD, Brogan D. A modified
  cluster-sampling method for post-disaster rapid
  assessment of needs. Bull World Health Organ.
  199674(4)399-405.
• 8. Centers for Disease Control and Prevention.
  Rapid community health and needs assessments
  after Hurricanes Isabel and CharleyNorth
  Carolina, 20032004. MMWR Morb Mortal Wkly Rep.
  200453840-842.

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References

• 1. Frerichs RR, Shaheen MA. Small-community-based
  surveys. Annu Rev Public Health. 200122231-247.
• 2. Horney J, Snider C, Gammons L, Ramsey S.
  Factors associated with hurricane preparedness
  Results of a pre-hurricane assessment. J Natural
  Dis. 20083(2)143-149.