Tabulation and Dual System of Estimation (DSE) Pres. 9 United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009

Tabulations & Dual System of Estimation (DSE) Tabulations: Initial tables Estimated number of non-movers Estimated number of out-movers Estimated number of matched non-movers Estimated number of matched out-movers Estimated in-movers Estimated number of erroneous inclusions in the census Estimated number of correctly enumerated persons United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 2

Basic Tabulations for Coverage Analysis Tabulations for coverage estimates (by age group & sex) E-sample estimates of population enumerated in the census P-sample estimates of total population Census omissions & census omission rates Census erroneous inclusions & census erroneous inclusion rates Preliminary DSE of True Population Net census coverage error and net coverage rate Gross census coverage error & rate Final DSE of True Population United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 3

Examples - Tabulations for Content Error Estimates Sex as reported in the census and as reported in the PES for matched persons Age as reported in the census and as reported in the PES for matched persons Family relationship as reported in PES for matched persons NOTE: PES should check content errors only for those items that support PES procedures United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 4

Dual System of Estimation (DSE) Omissions not a complete story in evaluating a census Census, as earlier stated, can contain duplicates Census can erroneously enumerate some one who should have been enumerated elsewhere Fictitious persons - in some cases Net coverage error Therefore need to estimate True Population United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 5

Dual System of Estimation (DSE) (contd.) In census Out of census In PES Out of PES Total United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 6

Dual System of Estimation (DSE) (contd.) Chandrasekaran-Deming estimator (1949) assuming independence United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 7

Dual System of Estimation (DSE) (contd.) The form of DSE used in PES is as follows: Where C = census count II = number of persons with insufficient information CE = estimated number of correct enumeration from the E-sample Ne = estimated number of people from the E-sample Np = estimated number of people from the P-sample M = estimated number of persons from the P-sample population who matched to the census United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 8

Dual System of Estimation (DSE) (contd.) Coverage rate This is the matched population relative to estimated PES population The DSE is usually applied within substrata/subgroups formed e.g. sex and age - groups United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 9

Dual System of Estimation (DSE) (contd.) Erroneous inclusions rate This is equal to the total number of persons erroneously included in census relative to the Census population estimated by E-sample United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 10

Dual System of Estimation (DSE) (contd.) Matched population Matched population = Matched non-movers + estimated matched out-movers (thus, in practice, the number of out-movers is assumed to be the same as that of in-movers) Census population estimate Census population = Matched non-movers+ matched out-movers + population erroneously included in the census+ population correctly enumerated in the census but missed in the PES United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 11

Dual System of Estimation (DSE) (contd.) Estimated PES population PES population = Census + omission – Erroneous PES population = Number of non-movers + in-movers Omission population Omissions = PES population - (Census – erroneous) = PES population - Census + Erroneous United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 12

Dual System of Estimation (DSE) (contd.) Omission rate Is the missed population between the census and PES relative to PES population United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 13

Dual System of Estimation (DSE) (contd.) True population True Population = estimated PES population multiplied by population from the census after subtraction of erroneous enumerations and divided by matched population between the census and the PES United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 14

Dual System of Estimation (DSE) (contd.) Net coverage error The difference between what should have been counted, thus True Population and what was counted in the census Net Coverage rate The measure is the total net error relative to the DSE estimate of the true population (an important indicator of the quality of census coverage) United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 15

Dual System of Estimation (DSE) (contd.) Gross coverage error The sum of Omissions and Erroneous Inclusions Gross coverage error rate per unit enumeration This is the absolute gross error relative to census enumerated population United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 16

Evaluation of Content Error Net difference rate (NDR) The NDR is the difference between the number of cases in the census and number of cases in the PES that fall under a category (e.g. age-group) relative to the total number of matched persons in all response categories United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 17

Evaluation of Content Error (contd.) Index of inconsistency It is a relative number of cases for which the response varied between the census and PES. In a n x n table, numbers in diagonal cells show consistency (agreement). Off diagonal numbers represent inconsistency. This is calculated for each response from a category United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 18

Evaluation of Content Error (contd.) Other measures include: It is Aggregate index of inconsistency Gross difference rate Rate of agreement United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 19

How to interpret content error measures Index Low Moderate High Absolute value of NDR < 0.01 0.01-0.05 >0.05 Index of Inconsistency <20 20-50 >50 Aggregate Index of Inconsistency United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009 20

Thank You! United Nations Regional Workshop on the 2010 World Programme on Population and Housing Censuses: Census Evaluation and Post Enumeration Surveys, Asunción, Paraguay, 3-7 August 2009