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Collaborative Public Health Field Course January 2010. LECTURE#3 Data: Uses, Abuses & Analysis Marcia C. Castro mcastro@hsph.harvard.edu. Objectives. Describe types of data available for health-related research Introduce basic demographic methods Describe spatial analytical approaches
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Collaborative Public Health Field Course January 2010 • LECTURE#3 • Data: Uses, Abuses & Analysis • Marcia C. Castro • mcastro@hsph.harvard.edu
Objectives • Describe types of data available for health-related research • Introduce basic demographic methods • Describe spatial analytical approaches • GIS, Remote Sensing, and Spatial Analysis
Data Sources • Three types of data: • Events • Cases & deaths • Exposure (“denominators”) • Population • “Clues” on transmission mechanisms • Multidisciplinary: social, economic, demographic, behavior & individual perception/knowledge, ecological, political, biological
Data Sources • What are we looking for? • Time • Space • Population groups you can’t always get what you want
Data Sources: Events • Administrative data • Outpatient / Hospitalization • Reported cases • Active / Passive • Immunization • Deaths • Control activities • Survey-based data • Sample frame
Data Sources: Denominators • Population counts • Census • Every 10 years • Civil registration system • Coverage • Household surveys • Sample • Periodicity & Coverage • Projections • Uncertainty
Data Sources: Multidisciplinary • Census & household surveys • Agriculture • Environment • Land cover, land change, land use • Climate • Soil, hydrology • Infrastructure • Urban planning & expansion • Social programs (“cash transfers”)
Demographic Methods • Population (P) numbers can only change by • Births (B) Fertility • Deaths (D) Mortality • Movements in (I) / out (E) Migration • Measuring each component • Direct methods • Indirect methods
Demographic MethodsMortality • Key indicators: • Infant & Child mortality • Life expectancy at birth
160 1996 (TFR = 2.5) 2006 (TFR = 1.8) 128 96 Age-spefic fertility rates (1,000) 64 32 0 15 20 25 30 35 40 45 50 Age Demographic MethodsFertility • Key indicator: Total Fertility Rate PNDS 1996 and 2006
Demographic MethodsMigration • Migratory flow • Direction • Intensity • Characteristics
Spatial MethodsSpace is special • Visualization • Exploration • Modeling
Framework for Spatial Data Analysis Attribute data Feature data Databases GIS & Remote Sensing Visualization Maps Describe significant patterns Exploration StatisticalSoftware Test hypotheses Modeling
Visualization Source:Map 1. Published by C.F. Cheffins, Lith, Southhampton Buildings, London, England, 1854in Snow, John. On the Mode of Communication of Cholera, 2nd Ed, John Churchill, New Burlington Street, London, England, 1855.
Visualization: prevalence rates Schistosomiasis Mansoni Bahia
Visualization: % variation in prevalence rates Schistosomiasis Mansoni Bahia
Virgin Mary in a pancake Mermaid in clouds Patterns?
Exploration: clustering Machadinho Settlement Project, Rondônia State, Brazilian Amazon Significant clusters of low malaria rates No significant clusters Significant clusters of high malaria rates
Modeling: diffusion Schistosomiasis
A final word of caution • Combining data … … from different sources … from different years … in different scales • Ecological X Individual analysis • Generalizability • Causality
References • Anselin, L. 2006. How (Not) to Lie with Spatial Statistics. American Journal of Preventive Medicine 30(2): S3-S6. • Brownstein, J.S., C.A. Cassa, K.D. Mandl. 2006. No place to hide: Re-identifying patients from published maps. New England Journal of Medicine 355(16):1741-2. • Kenneth Hill, Alan D Lopez, Kenji Shibuya, Prabhat Jha, on behalf of the Monitoring of Vital Events (MoVE) writing group. 2007. Interim measures for meeting needs for health sector data: births, deaths, and causes of death. The Lancet 370(9600): 1726-1735. • Werneck, GL et al. 2002. The urban spread of visceral leishmaniasis: clues from spatial analysis. Epidemiology 13(3):364-367.
Questions for Discussion:Data Sources • What are the main data limitations for health-related analysis? • What would be needed to fill in the gap(s)? • How could available data be used for evidence-based planning of public health interventions?
Questions for Discussion:Data Analysis • How would a demographic analysis improve understanding of the 5 diseases focused in this course? • How do the use of spatial tools in public health improve the understanding of disease dynamics? • Is there a balance between local x global analysis? • How can each approach inform policy makers? • Which is most appropriate to evaluate the progress toward achieving the MDG?