Summary

Recent natural disasters like the South Asian earthquake-tsunami in 2004 and the Pakistan earthquake and Hurricane Katrina in 2005 highlight the range of scales—from village to nation—at which populations can be affected by natural events and, similarly, the range of scales at which humanitarian assistance must be coordinated and delivered. In addition to sudden-onset natural disasters, which capture public attention and significantly underscore such critical outcomes as deaths and economic and livelihood losses, chronic disasters such as drought, famine or civil conflicts of a duration and severity that displace populations from their homes and livelihoods continue to demand international responses in the form of aid and reconstruction and must be addressed at local, regional, and national scales. Although specific data needs vary according to the type of disaster and regional issues, some basic necessities in responding to these events are population data and the ability of responders to use the data to deliver effective humanitarian aid. Population data allow determination of how much and what types of aid are needed and where the aid should be directed. Similarly, population data can be used in development and reconstruction efforts prior to and following a particular crisis. When population data are also geographically referenced, the versatility of combining data with maps becomes evident and generates potential for a great variety of products useful for the emergency response and development communities in planning and delivering aid.

A timely response and the delivery of disaster relief or humanitarian assistance is challenging in and of itself, yet decision makers often lack the requisite population data for the affected area, including the total number



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Tools and Methods for Estimating Populations at Risk from Natural Disasters and Complex Humanitarian Crises Summary Recent natural disasters like the South Asian earthquake-tsunami in 2004 and the Pakistan earthquake and Hurricane Katrina in 2005 highlight the range of scales—from village to nation—at which populations can be affected by natural events and, similarly, the range of scales at which humanitarian assistance must be coordinated and delivered. In addition to sudden-onset natural disasters, which capture public attention and significantly underscore such critical outcomes as deaths and economic and livelihood losses, chronic disasters such as drought, famine or civil conflicts of a duration and severity that displace populations from their homes and livelihoods continue to demand international responses in the form of aid and reconstruction and must be addressed at local, regional, and national scales. Although specific data needs vary according to the type of disaster and regional issues, some basic necessities in responding to these events are population data and the ability of responders to use the data to deliver effective humanitarian aid. Population data allow determination of how much and what types of aid are needed and where the aid should be directed. Similarly, population data can be used in development and reconstruction efforts prior to and following a particular crisis. When population data are also geographically referenced, the versatility of combining data with maps becomes evident and generates potential for a great variety of products useful for the emergency response and development communities in planning and delivering aid. A timely response and the delivery of disaster relief or humanitarian assistance is challenging in and of itself, yet decision makers often lack the requisite population data for the affected area, including the total number

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Tools and Methods for Estimating Populations at Risk from Natural Disasters and Complex Humanitarian Crises of people and their characteristics, density, and vital statistics—descriptors of the population that constitute its demographic features. Demographers study the characteristics and composition of human populations, in particular with reference to size and density, distribution, and vital statistics such as age, gender, fertility, mortality, and migration. Although location is implicit in these population analyses, the extent to which it is explicit varies tremendously. During humanitarian crises, it is not uncommon for humanitarian or emergency response teams to deploy without even rough estimates of the number and location, let alone ages and gender, of the people in the vicinity of the disaster. Even if the data are available, they are not always in a form that can be used by decision makers, and demographers are not always placed with the response teams. Once the initial emergency period has passed, accurate data on the characteristics and size of the population are also required for recovery, reconstruction, and resettlement. With the number of refugees and internally displaced populations in the world remaining close to 20 million for nearly a decade (UNHCR, 2006), the challenges in providing this type of assistance are constant and global, and inaccurate numbers and locations for populations in crisis can slow the relief effort and literally mean the difference between life and death (NRC, 2001). How do emergency response, aid, and development organizations receive, maintain, and disseminate timely information to know where and which populations are most at risk and likely to be affected by a disaster? The National Research Council Committee on the Effective Use of Data, Methodologies, and Technologies to Estimate Subnational Populations at Risk was convened to respond to a request from the U.S. Department of State, U.S. Agency for International Development (USAID), U.S. Census Bureau, National Aeronautics and Space Administration, and Centers for Disease Control and Prevention that considers this broad question, further refined in the study’s statement of task (Box 1). This committee report responds to that charge and provides the specific framework for understanding populations at risk of disasters and the need for good population data, including demographic features; it also describes how demographic data are used before, during, and after a crisis, as well as some of the more important reasons these data are underutilized. The report also examines the current status of techniques for estimating and analyzing at-risk populations, with an overview of the direct and proxy measures for making these population estimates, and outlines the inter- and intra-institutional challenges of data sharing and information management. The committee was asked to examine some examples of responses to crises in three specific countries—Mali, Mozambique, and Haiti—each with varying population data records at the times of specific crises. The report illustrates the manner in which population data and geographical visualization tools were and were not used in these responses, and how their use

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Tools and Methods for Estimating Populations at Risk from Natural Disasters and Complex Humanitarian Crises BOX 1 Statement of Task An ad hoc committee under the auspices of the Geographical Sciences Committee will conduct a study on improving demographic data, methods, and tools and their application (1) to better identify populations at risk—groups that are susceptible to the impact of natural or human-made disasters; and (2) to improve decisions on humanitarian intervention, disaster relief, development assistance, and security for those populations at subnational scales. The study will be organized around a workshop that will address the following tasks: Assess the strengths and weaknesses of existing data, methods (e.g., gaps in spatial and thematic coverage, counting individuals, proxy measures such as those derivable from Earth observations), and tools for estimating population. Identify the limitations of current institutional structures in using existing demographic and other data and tools for these applications, and potential new approaches resulting from science and technology advances for collecting better data and producing more effective information and analysis tools. Identify ways in which subnational demographic and geographic data and tools could be used to help decision makers in U.S. federal agencies, foreign governments, international organizations, and international partner organizations provide useful information to populations at risk of facing disasters as well as to better respond to their needs for humanitarian assistance. Review the strengths and limitations of information and data analysis and visualization tools developed by government agencies for responding to conflict-, climate-, and health-related crises in Mali, Mozambique, and Haiti. Informed by this three-country example, recommend ways to make information collection and data analysis and visualization tools more effective for decision makers responding to humanitarian crises. might have been improved. While directed primarily at the U.S. government sponsors of the study, the main recommendations identify dedicated actions with respect to population data that might improve the ability of federal agencies and international organizations, national governments, institutes, and private entities to conduct timely, effective disaster response and development work. ACCURATE, ACCESSIBLE, AND GEOSPATIALLY RESOLVED SUBNATIONAL POPULATION DATA National census data serve as the foundation for measuring likely populations at risk from the impacts of natural or human-induced disasters. Census data include not just the number of people but also some of the

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Tools and Methods for Estimating Populations at Risk from Natural Disasters and Complex Humanitarian Crises characteristics of the population such as age, gender, and race or ethnicity; these categories are commonly described as demographic data. In many countries, data on economic well-being and housing stock are included as well. In this report, the broader term “population data” is used to encompass both the number of people and their demographic and other socioeconomic characteristics such as those typically collected through censuses and surveys. Improvements in the collection of and access to subnational data are vital to decisions on humanitarian intervention, disaster relief, and development assistance. However, various acute, but in many cases resolvable, limitations in geospatial data, methods, and tools for improvements in subnational demographic data estimations often preclude the use of the data under normal conditions for planning, let alone during periods of crises. In this view, the committee found that assessments of at-risk populations involve a linkage between population data by location (place or area), frequency and severity of a specific kind of hazard or sets of hazards acting on that location, and the resilience (coping capacity) of societal and environmental subsystems of that location. In other words, the quality and level of population data will have a direct effect on the quality of the response and the number of lives saved. Based on information gathered during the course of the study and on its own expertise, the committee has reached an overarching conclusion 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 this information to enhance the distribution of disaster relief aid. The committee’s recommendations to agencies and organizations working in relief and development capacities support this conclusion and specifically address improvement of the institutional capacity for a baseline census; improvements in the base census and the release, availability, and archiving of data; institutional and decision-making needs; research needs; and the interorganizational structure of U.S. government data providers (Box 2). Improvement of the Institutional Capacity for a Baseline Census Estimation of the total population at risk and definition of its characteristics (e.g., age, gender) and its subnational and spatial distributions are critical for mounting any humanitarian response. While the expense and resource commitments needed to conduct national censuses with greater than 10-year frequency may prohibit obtaining these data more often, simple algorithms could be used to update the census population data

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Tools and Methods for Estimating Populations at Risk from Natural Disasters and Complex Humanitarian Crises BOX 2 Summary of Study Recommendations Improvement of the Institutional Capacity for a Baseline Census Improve the capacity of census-poor countries, through training and technical assistance programs, to undertake censuses. Such improvement is critical for the long-term availability of subnational data that can 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 understanding of disasters. These data sets should have pre-existing protocols for data format, sharing, mapping, intercensal projections, and metadata that are consistent with international standards. Integrate the national statistical offices (NSOs) into the national preparedness and response teams for national emergencies. This role would involve the development of pre-disaster geospatial databases and experience in working at subnational levels relevant to hazards of all kinds. The aim is to improve the capacity of NSOs to generate and modify existing data in a timely fashion to enhance emergency response and crisis decision making. National and international disaster response and humanitarian agencies and organizations should elevate the importance of demographic and specifically spatial demographic training for staff members. Further, census staff and others working in NSOs throughout the world should be encouraged to undertake such training in order to promote the analysis and use of subnational data before, during, and after emergency response situations. Improvements in the Base Census and the Release, Availability, and Archiving of Data Develop a template of minimum acceptable population and other geospatial data sets that are required by disaster responders. The data sets should be updated frequently (at least mid-decade if not more frequently) and include digital census enumeration units and other census maps in digital form. The standard of open-access census data and sharing (as practiced, for example, by Brazil, South Africa, and the United States) should serve as a model for other agencies and for countries that currently do not operate in an open geospatial environment. This access includes spatial data such as digital boundary files of subnational units of countries of the world. Governments should release specific data sets that are vital to disaster planning and response. Furthermore, international standards should be developed for the release of subnational population data to maintain confidentiality. Countries financially unable to comply with confidentiality standards should be offered incentives to do so. Establish a centralized system of access, such as distributed archives and data centers for publicly available subnational data, including data from surveys. The archives would function as such a repository for shared local data and would have the primary responsibility for re-dissemination of data to the appropriate response communities during a disaster. The archives should build upon existing data resources.

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Tools and Methods for Estimating Populations at Risk from Natural Disasters and Complex Humanitarian Crises Institutional and Decision-Making Needs Relief agencies should broaden their collaborative relationships with NSOs to ensure the acquisition of real- and near-real-time data that complement and are compatible with existing data used for disaster response. Research Needs Support should be given to test the accuracy of estimates of size and distribution 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 render global spatial population estimation—LandScan and Gridded Population of the World—use different methodologies. An independent study of the state of the art in spatial population estimation would highlight the strengths and weaknesses of the existing methods, and could serve as a guide for improvements in the methods and development of new ones for the purposes of understanding populations at risk. Improve subnational analyses of vulnerability to natural disasters and conflict in order to delineate hazard zones or exposures where routine, periodic data collection ex ante could occur. The development of such georeferenced vulnerability analyses could help provide accountability to decision makers in preparedness and prevention and establish priorities for risk reduction investments by all stakeholders. Interorganizational Structure of U.S. Government Data Providers The U.S. Census Bureau should be given greater responsibility for understanding populations at risk and should be funded to do so. These responsibilities could include greater capacity and authority for training international demographic professionals in the tools and methods described in this report, and providing data and analytical capabilities to support the U.S. government in international disaster response and humanitarian assistance activities. The U.S. Census Bureau should also have an active research program in using and developing these tools and methods, including remotely sensed imagery and field surveys. Existing research support models that involve government-academic-private consortia could be explored to develop a framework for the U.S. Census Bureau to adopt these added responsibilities. with information from ongoing demographic surveys conducted between censuses. These methods are rarely employed in pre-disaster preparedness or in post-disaster response situations. At the time of the October 2005 Pakistan earthquake, the census data in Pakistan were seven years old and not fully representative of the characteristics of the subnational populations affected by the event. The experience of the humanitarian aid response to the earthquake exemplified that census data, supplemented by more recent population survey updates provided in real time to responders, would have

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Tools and Methods for Estimating Populations at Risk from Natural Disasters and Complex Humanitarian Crises improved aid planning and allocation after the earthquake struck. Although various methodologies for conducting intercensal surveys are well established, the committee notes that surveys are not routinely used to update census information, and the smaller numbers of observations that generally comprise a typical survey are not always easily integrated into existing census databases. Thus, methods for integrating survey and census data for this purpose need to be developed and tested by teams of researchers and relief practitioners. Good population data and their use in humanitarian situations are also predicated on the existence of staff trained in both demography and geospatial tools and technologies at national statistical offices (NSOs) in each country. The committee found that, at present, relatively few NSOs, especially in developing countries, have sufficient trained expertise in both demography and geospatial tools and technologies. Building appropriate skill sets and establishing more formalized training in countries lacking demographers and people with geospatial expertise are a fundamental part of NSO development. Such training programs could be part of overall capacity building with funding by bilateral aid programs, such as USAID, or through broader country capacity building programs, such as those supported by the World Bank or the United Nations. Improvements in the Base Census and the Release, Availability, and Archiving of Data The issue of determining populations at risk involves more than just data; however, every community needs accurate and place-specific population and population attribute data for improved disaster planning and response. Georeferenced total population and age-gender specific counts are thus the minimum data sets required for disaster response. Population attribute data such as race or ethnicity, socioeconomic status, and education are also important and serve to improve the effectiveness of the response. Examination of existing data and methods for estimating subnational populations led the committee to understand that the methods themselves are likely less problematic than the data to which estimation techniques are applied, especially in those countries that are data poor. Censuses, surveys, and remotely sensed imagery, as well as modeling techniques, can be applied to overcome deficiencies in the data sources. While it may be impractical (and potentially problematic from the standpoint of privacy) to obtain 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 areas 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

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Tools and Methods for Estimating Populations at Risk from Natural Disasters and Complex Humanitarian Crises unit ought to be georeferenced and provided in digital form with hard-copy maps available for field responders. A persistent limitation on the effective use of subnational population data is the low level of access to sensitive data and of data sharing among agencies and organizations. A practical issue that may hinder data sharing, for example, is that governments may charge for access to data as part of their cost recovery plans for the initial expense of data collection, analysis, and management. A direct result of cost recovery programs is that data are not freely available to those requesting them for the purpose of humanitarian assistance. Some national examples of open-access census data and sharing should serve as models to make census and administrative boundary data freely accessible; the response community may also consider negotiating appropriate reimbursement costs to the government agencies that collected the data. 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—an “Archive and Data Center”—for subnational population data worldwide. To be successful, countries contributing subnational data must be assured of confidentiality protections. Equally important are consistent protocols for inclusion, standardization, georeferencing, and analysis of the population data in such an archive. Institutional and Decision-Making Needs Although 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 are destroyed, how many people were displaced and where they went, and designated shelters or camps. It is beyond the capability of many NSOs to conduct field surveys of affected populations living outside of officially designated camps or to obtain ancillary data (e.g., 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, and do not duplicate, existing data sets for disaster and humanitarian relief. Research Needs The committee identified various approaches both to population size estimation as well and to understanding the vulnerability of subnational

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Tools and Methods for Estimating Populations at Risk from Natural Disasters and Complex Humanitarian Crises groups. At present, a number of differing approaches exist for spatial population estimation, but little guidance is provided as to which are most useful to local responders and in what circumstances. In addition to research on spatial population estimation methods, more analytical work is needed on subnational vulnerability analyses, an area that is now demanding more attention with the adoption of the Hyogo Framework of Action 2005-2015 by the international community at the 2005 United Nations World Conference on Disaster Reduction. Interorganizational Structure of U.S. Government Data Providers Prioritizing 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 exact compositions of the populations at risk including total numbers, characteristics, and location are often imprecise or unknown, which complicate humanitarian relief and disaster response efforts, even if local governments and agencies are willing to make existing population numbers available to responders. Lack of data access or absence of coordinated data analysis and response in the presence of population data poses problems not only for the world’s poorest nations, but also for the wealthiest. The recommendations resulting from this study provide a potential pathway for U.S. government agencies to improve population data estimates and their application to the identification of at-risk populations. Other international organizations, agencies, and governmental and nongovernmental groups involved in disaster response and development aid may also find implementation of some of these recommendations useful. These recommendations can help improve decision making on disaster relief and humanitarian intervention during a given crisis event and, importantly, recovery and development assistance efforts outside the crisis period. The committee understands that these recommendations involve allocation of additional financial resources in an environment of intense domestic and international competition for funds to support a host of worthy and practical programs and causes. The information in this report is intended to inform governments and donors about the longer-term benefit of investment in establishing and maintaining regularly updated georeferenced population data sets in all countries, with flexibility for disaggregation of the data to

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Tools and Methods for Estimating Populations at Risk from Natural Disasters and Complex Humanitarian Crises subnational levels. Governments and donors must determine themselves if and to what degree additional investment in these efforts is justified in the context of national spending priorities. REFERENCES NRC (National Research Council), 2001. Forced Migration and Mortality. Washington, D.C.: National Academy Press, 145 pp. UNHCR (United Nations High Commissioner for Refugees), 2006. The 2005 Global Refugee Trends: Statistical overview of populations of refugees, asylum seekers, internally displaced persons, stateless persons, and other persons of concern to UNHCR. Available online at http://www.unhcr.org/statistics/STATISTICS/4486ceb12.pdf [accessed October 4, 2006].