National census data serve as the foundation for measuring populations at risk from the impacts of natural or human-induced disasters. Improvements in subnational data are vital to enhance decisions on humanitarian intervention, disaster relief, and development assistance to populations vulnerable to a wide range of hazards potentially leading to disasters. Yet various acute, but in many cases resolvable, limitations in geospatial data, methods, and tools for improvements of subnational demographic data often preclude their use under normal conditions for planning, let alone during periods of crises.

Recognition of these needs and limitations leads us to reinforce at least two principal findings of other National Research Council (NRC) committees and reports. The report of the Committee on Planning for Catastrophe, Successful Response Starts with a Map: Improving Geospatial Support for Disaster Management (2007), found, and this committee reaffirms, that “in all aspects of emergency management, geospatial data and tools have the potential to contribute to the saving of lives, the limitation of damage, and the reduction in the costs to society of dealing with emergencies” (p. 2). The committee concurs as well with the NRC (2002) report Down to Earth that “USAID [United States Agency for International Development] and the U.S. Bureau of the Census should provide financial and technical support to national census offices and bureaus in Africa to help them complete censuses, geographically reference the data, and make the data available in disaggregated form to decision makers” (p. 66). The committee would, however, expand the geographical reference to Africa to include developing countries worldwide.

Moving beyond these reinforcing findings, our overarching conclusion is that the data and analytical capacity or potential capacity to address populations at risk exceeds the actual use of such data and appropriate analysis as judged by recent disasters in the United States and globally. Further, governments, emergency response organizations, and other types of responders need to be educated and trained in the importance, need, use, and contributions of such data and to be proactive in seeking and utilizing such information to enhance the distribution of disaster relief aid. The recommendations that follow represent the basic themes and issues that should be addressed to begin to make improvements in the operational environment and policy context for disaster relief and humanitarian intervention. It is noteworthy, however, that readily available, appropriate data and advanced analytical capacities alone do not ensure robust preparedness planning or responses to disasters or humanitarian crises. In the end, appropriate interagency coordination and cooperation hold the key to the timely and effective use of data and analysis for disaster response and human emergencies.

This report makes 10 major recommendations pertinent to improving assessments of populations at risk for the decision-making community at large and for agencies responsible for making such assessments on behalf of the United States and other bilateral and international actors. The first three recommendations address the improvement of the institutional capacity for a baseline census.

The need for subnational population data that are current and provided in real time is the key to effective planning and responses to disaster or humanitarian crises. Estimation of the total population at risk is critical as are the characteristics of that population (e.g., age, gender). The spatial referencing not only of the population data but also of other ancillary data, such as road networks, shelter availability, and so on is a key foundational layer for planning and mounting any humanitarian response.

1. Improve the capacity of census-poor countries, through training andtechnical assistance programs, to undertake censuses. Such improvement is critical for the long-term availability of subnational data thatcan assist in humanitarian emergency and development situations.Knowing the location, number, and critical characteristics of populations is pivotal to all planning, response, and long-term understandingof disasters. These data sets should have pre-existing protocols for dataformat, sharing, mapping, intercensal projections, and metadata thatare consistent with international standards.

One of the obstacles to the full employment of spatial demographic data during disasters, despite the clear need to do so, is the pressing human

resource issue. Responding to disasters and humanitarian crises requires shared geographic and demographic thinking and training. At present, there are relatively few units, especially in developing countries, with sufficient trained expertise in both demography and geospatial tools and technologies. Improvements in training and commitment by the national statistical office (NSO) and other staff for each country to include both demographic projection methodology in local areas and the use of appropriate spatial administrative units in map form are essential. There are a number of mechanisms for building such capacity, the first of which is recognizing the importance of the skill sets required for disaster preparedness and response. The second is formalized training. Such training programs could be part of overall capacity building and funded by bilateral aid programs, such as USAID, or through broader country capacity-building programs, such as those supported by the World Bank or United Nations. The United States experience suggests that improvement in the capacity to prepare for and respond to disasters saves lives and reduces economic costs when the event occurs.

2. Integrate the national statistical offices (NSOs) into the national preparedness and response teams for national emergencies. This rolewould involve the development of pre-disaster geospatial databasesand experience in working at subnational levels relevant to hazards ofall kinds. The aim is to improve the capacity of NSOs to generate andmodify existing data in a timely fashion to enhance emergency responseand crisis decision making.

3. National and international disaster response and humanitarian agenciesand organizations should elevate the importance of demographic andspecifically spatial demographic training for staff members. Further,census staff and others working in NSOs throughout the world shouldbe encouraged to undertake such training in order to promote theanalysis and use of subnational data before, during, and after emergency response situations.

The next set of recommendations highlights the need for improvements in the base census and the release, availability, and archiving of data. Every community needs accurate, place-specific population and population attribute data for improved disaster planning and response. The most critical data are total population and age-specific counts at the finest geographic scale possible. The level of geography (spatial resolution) is essential as well. While it may be impractical to get individual household data, aggregate counts by census tract or small enumeration area are key to effective disaster management. Equally important is the ability to aggregate these enumeration units into other geographies or spatial units, such as physical

zones (e.g., coastal areas, steep slopes, floodplains) or social zones (e.g., urban areas). The enumeration unit must be georeferenced and provided in digital (polygon) form with hard-copy maps available for field responders. The georeferenced total population and age- and gender-specific counts are the minimum data sets required for disaster response. Population attribute data such as race or ethnicity, religion, socioeconomic status, and education are important as well and will improve the effectiveness of the response. It goes without saying that all data should be as accurate as possible and consistent with standard estimation methods and their statistical confidence.

4. Develop a template of minimum acceptable population and other geospatial data sets that are required by disaster responders. The datasets should be updated frequently (at least mid-decade if not more frequently) and include digital census enumeration units and other censusmaps in digital form.

One of the most persistent limitations to the effective use of subnational population data is the low level of access to sensitive data and of data sharing among agencies and organizations. As noted above, this impediment is also true within countries such as the United States (see NRC, 2007). Data sharing between different agencies or parts of agencies is a medium-term goal. In the short term, greater sharing between agencies with disaster response and humanitarian assistance purposes is paramount.

It is common practice in many countries for governments to charge for access to data. One-time use fees or common licensing agreements enable statistical agencies to generate a revenue stream for their work and products. This cost recovery process enables the agency to recoup some of its expenses in data collection, data analysis, and data management. One of the drawbacks to cost recovery is that data are not freely available and issues of reimbursement costs often delay the acquisition of population and geographic data for use in planning and response to emergencies. Therefore, strong incentives should be put in place to make census and administrative boundary data freely accessible, even if this means a government subsidy to ensure wide and equitable access. Further, some appropriate reimbursement costs to the government agencies that collected the data should be negotiated between governments and the responder community. Special protocols could be developed to ensure timely access to detailed census data by humanitarian agencies in times of crisis.

5. The standard of open-access census data and sharing (as practiced, forexample, by Brazil, South Africa, and the United States) should serveas a model for other agencies and for countries that currently do notoperate in an open geospatial environment. This access includes spatial

data such as digital boundary files of subnational units of countries ofthe world. Governments should release specific data sets that are vitalto disaster planning and response. Furthermore, international standardsshould be developed for the release of subnational population data tomaintain confidentiality. Countries financially unable to comply withconfidentiality standards should be offered incentives to do so.

Large differences in access to the requisite data and in data sharing exist among countries. The more restrictive cases effectively inhibit disaster planning and responses. Given the increasing international character of disaster response, the decision-making communities would benefit not only from access to the required data but from maintenance of appropriate safeguards regarding data confidentiality.

One such mechanism is a centralized repository for subnational population data worldwide. This Archive and Data Center could take a variety of forms based on such existing models as Interuniversity Consortium for Political and Social Research and the Integrated Public Use Microdata Series, and could be administratively located in the United Nations, a nongovernmental organization, in a UN-university consortium made up of key players, or the U.S. Census Bureau’s Populations Division. Funding could be provided by aid agencies such as the World Bank or USAID. To be successful, countries contributing subnational data ought to be assured of confidentiality protections. Approaches such as those that will likely result from the 2007 Africa Symposium on Statistical Development (January 2007, Kigali, Rwanda) with a symposium theme of “Africa Counts: Towards a Complete Enumeration of the African Population and Housing Censuses” (http://www.statssa.gov.za/asc2007/index.asp) may outline collaborative solutions between African countries and research and analytical institutions toward establishing such a data archive for Africa. Part of any such effort, regardless of the location of the coordinating organization, is the need for consistent protocols for inclusion, standardization, georeferencing, and analysis of the population data included in such an archive.

6. Establish a centralized system of access, such as distributed archives anddata centers for publicly available subnational data, including data fromsurveys. The archives would function as a repository for shared localdata and would have the primary responsibility for re-dissemination ofdata to the appropriate response communities during a disaster. Thearchives should build upon existing data resources.

The next set of recommendations focuses on institutional and decision-making needs. There are many instances in which disaster response and assistance decisions are made in the absence of credible data from the field.

While agencies commonly anticipate data and information needs in advance (the preparedness phase), oftentimes other critical informational needs arise during and after the event (response phase)—such as which road networks were destroyed, how many people were displaced, and where they went, in addition to the designated shelters or camps. It is beyond the capability of many NSOs to conduct field surveys of affected populations living outside officially designated camps or to obtain ancillary data (such as fixed-wing airborne imagery or satellite imagery) to assist in determining the number and characteristics of the affected populations. Relief agencies, in contrast, typically have this capacity and should work closely with local NSOs to ensure that such data complement not duplicate, existing data sets for disaster and humanitarian relief. Therefore, the committee recommends the following:

7. Relief agencies should broaden their collaborative relationships withNSOs to ensure the acquisition of real- and near-real-time data thatcomplement and are compatible with existing data used for disasterresponse.

One of the charges to the committee was to assess the strengths and weaknesses of the existing methods and proxy measures for estimating vulnerable populations. The committee found various approaches both to population size estimation and to approaches to understanding the vulnerability of subnational groups. To better identify at-risk populations, additional research is warranted to ascertain which approaches or methodologies might prove the most successful. At present, there are a number of differing approaches to spatial population estimation, but little guidance as to which are most useful to local responders. At the same time, there is little consistent information on the subnational delineation of hazard exposures and georeferenced vulnerability analyses. Additional research into subnational vulnerability assessments could help to establish a scientific basis for risk reduction investments.

8. Support should be given to test the accuracy of estimates of size anddistribution of populations based on remotely sensed imagery, particularly in rural and urban areas of countries with spatially, demographically, and temporally inadequate census data. Current efforts to renderglobal spatial population estimation—LandScan and Gridded Population of the World—use different methodologies. An independent studyof the state of the art in spatial population estimation would highlightthe strengths and weaknesses of existing methods and could serve as aguide for improvements in the methods and development of new onesfor the purposes of understanding populations at risk.

9. Improve subnational analyses of vulnerability to natural disasters andconflict in order to delineate hazard zones or exposures where routine,periodic data collection ex ante could occur. The development of suchgeoreferenced vulnerability analyses could help provide accountabilityto decision makers in preparedness and prevention and establish priorities for risk reduction investments by all stakeholders.

How to prioritize resources for preparedness and response is one of the most vexing aspects of disaster and humanitarian crisis management. Objective data on hazard vulnerability and population are often lacking, as are subnational population data. Tensions and impediments exist between federal agencies with respect to spatial and demographic data for disasters and humanitarian crises. From an operational and policy standpoint, these issues lead to inefficiencies and are often duplicative of human and financial resources. The committee’s last recommendation addresses the interorganizational structure of U.S. government data providers.

10. The U.S. Census Bureau should be given greater responsibility for understanding populations at risk and should be funded to do so. Theseresponsibilities could include greater capacity and authority for training international demographic professionals in the tools and methodsdescribed in this report, and providing data and analytical capabilitiesto support the U.S. government in international disaster response andhumanitarian assistance activities. The U.S. Census Bureau should alsohave an active research program in using and developing these toolsand methods, including remotely sensed imagery and field surveys.Existing research support models that involve government-academicprivate consortia could be explored to develop a framework for theU.S. Census Bureau to adopt these added responsibilities.

Taken together, these recommendations provide a pathway for improving demographic data, methods, and tools and their application to the identification of at-risk populations. Carefully planned and implemented, they would help improve decision making on disaster relief, humanitarian intervention, and recovery and development assistance after the initial crisis subsides.

NRC (National Research Council), 2002. Down to Earth: Geographic Information for Sustainable Development in Africa. Washington, D.C.: The National Academies Press.

NRC, 2007. Successful Response Starts with a Map: Improving Geospatial Support for Disaster Management. Washington, D.C.: The National Academies Press.

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