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WHO practices in imputation and estimation. Conference on Data Quality for International Organizations Rome, Italy, 7-8 July 2008-05-28. Carla AbouZahr Coordinator, Statistics, Monitoring and Analysis World Health Organization Geneva. Types of health statistics.
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WHO practices in imputation and estimation Conference on Data Quality for International Organizations Rome, Italy, 7-8 July 2008-05-28 Carla AbouZahrCoordinator, Statistics, Monitoring and AnalysisWorld Health OrganizationGeneva Health Statistics & Informatics
Types of health statistics • Unadjusted health statistics derived directly from primary data collection with no adjustments or corrections. Health Statistics & Informatics
Types of health statistics • Unadjusted health statistics derived directly from primary data collection with no adjustments or corrections. • Adjusted health statistics corrected to deal with known biases, use of indirect techniques. Health Statistics & Informatics
Types of health statistics • Unadjusted health statistics derived directly from primary data collection with no adjustments or corrections. • Adjusted health statistics corrected to deal with known biases, use of indirect techniques. • Predicted health statistics based on a model relating the quantity of interest to covariates. • Forecasting: past relationships to predict future • Farcasting: missing primary data Health Statistics & Informatics
Source: Gareth Jones WHO/UNICEF database Health Statistics & Informatics
Source: Christopher Murray Institute for Health Metrics and Evaluation Health Statistics & Informatics
Sources of data for global mortality estimates (circa 2004) Adult mortality: 45q15 Child mortality: q5 Birth histories, Indirect methods; ? Indirect methods problematic for adult mortality Source: WHO Health Statistics & Informatics
WHO principles for imputation • Standard four-step procedure for estimation • a high-quality accessible database; • an independent peer review group; • published methods of estimation; margins of uncertainty • internal WHO clearance by HSI • Country consultation • iterative process between Member States, WHO country and regional offices and headquarters • feedback on quality of data collection and reporting; strengthening country capacity to reproduce, produce and use estimates. Health Statistics & Informatics
External advisory bodies • Disease-specific M&E reference groups • Include agencies and academic experts • Address coordination issues • Develop "best estimates": <5, maternal mortality, coverage of interventions • Advisory Committee on Health Monitoring and Statistics (ACHMS) • Independent outside experts • Gives inputs to WHO on its work, including Global Burden of Disease, World Health Statistics. • Advises DG on scientific and technical issues. Health Statistics & Informatics
Summary and conclusion • WHO use of imputation: • Correction for definitional differences, application of WHO standards, known biases • Production of regional aggregates • Generation of missing values for countries • Recommendations for CCSA • General principles for imputation • Methods context and subject specific • Transparency and replicability • Country endorsement of methods not values Health Statistics & Informatics