Rapid Needs Assessments and GIS

1. Rapid Needs Assessments and GIS

2. 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

3. 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)

4. 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)

5. 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

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

7. 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 • 1970’s – 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

8. 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

9. 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)

10. 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)

11. 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

12. Modified EPI Cluster Sampling • Disaster site divided into blocks/clusters • First stage, a sample of n clusters (n=30 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 (k=30 as in EPI method): • Interview conducted at each housing unit

13. Modified EPI Cluster Sampling • Interviewer makes multiple attempts to conduct an interview at a selected housing unit • EPI method—interviewer 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

14. 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

15. 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)

16. 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

17. 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

18. 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

19. 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

20. References • 1. Surveillance and rapid needs assessment. Centers for Disease Control and Prevention. Web site. http://www.cdc.gov/nceh/hsb/disaster/surveillance.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. 1993;22:1715-1720. • 3. World Health Organization. Rapid health assessment proocols for emergencies. Geneva, Switzerland: World Health Organization; 1999:1. • 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.

21. 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. 1985;38:65-75. • 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. 1994;23(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. 1996;74(4):399-405. • 8. Centers for Disease Control and Prevention. Rapid community health and needs assessments after Hurricanes Isabel and Charley—North Carolina, 2003—2004. MMWR Morb Mortal Wkly Rep. 2004;53:840-842.

22. References • 1. Frerichs RR, Shaheen MA. Small-community-based surveys. Annu Rev Public Health. 2001;22:231-247. • 2. Horney J, Snider C, Gammons L, Ramsey S. Factors associated with hurricane preparedness: Results of a pre-hurricane assessment. J Natural Dis. 2008;3(2):143-149.