1 The Structure of Error Components in 2010 Census Coverage Error Estimation: P-sample estimates Mary H. Mulry & Bruce D. Spencer U.S. Census Bureau Northwestern Univ International Total Survey Error Workshop June 15, 2010

2 Census Coverage Error Net error = omissions – erroneous enumerations = True Pop – census DSE used to estimate True Pop Enumeration sample (E-sample) Population sample (P-sample) Components of census coverage: Erroneous enumerations Omissions = net error + erroneous enumerations (weighted P-sample not suitable for component error)

3 Error structure for component errors Recent studies (Mulry , Spencer ) Have general design for simulation to study synthesis of sampling and nonsampling errors Have decompositions of E-sample & P-sample nonsampling errors as functions of field & processing errors for net error & component errors Have considered the data available from evaluations E-sample models presented at 2009 ITSEW

Dual System Estimator 4 DSE = Enumerations not imputed Correct enumeration rate __________________________________________ Match rate from P-sample

5 Focus on P-sample Match rate estimates census enumeration rate for DSE Sample selected independent of census 170,000 HUs in US; 7,500 HUs in Puerto Rico Interviews conducted Aug – Oct 2010 Census Day was April 1, 2010 Followup conducted early 2011 a fter initial matching to collect more info on unresolveds Final matching after Followup

6 P-sample seeks to answer to 2 questions Is person in the P-sample? Has to live in HU on Census Day Complication for usual residence: Some move between Census Day & Interview Day Does the person have a matching census enumeration at usual residence on Census Day?

Interview asks (paraphrased) Who lives here now? Did each person live here on Census Day? If not, where did the person live? includes probes to aid memory Did anyone else live here on Census Day? If yes, where did they move? 7

People in P-sample 8 In-mover moves into sample block after Census Day P-sample out-mover moves to Group Quarters or out of US after Census Day Stable Resident lives in sample block on Census Day & Interview Day Sample block

P-sample status 9 Yellow = in the P-sample

10 Types of errors in data affecting P-sample status Membership in housing unit population Usual residence on Interview Day Usual residences on both Census Day & Interview Day Geocoding housing unit interviewed

11 How errors in P-sample status occur Failure to detect False detection Types of errors Population member IntD usual residence CenD & IntD usual res. Geocoding

Truth: Stable Resident in P-sample 12 Int Day in HU out of sample NP out-mover Error Coded out of sample Interloper Int Day & Cen Day in HUs out of sample Not in HU Pop (GQ or out of US on Cen Day) Out-of-scope

13 Errors in data causing errors in match status Usual residence on Census Day Causes search for match to look in wrong place Identification of census enumeration Geocoding housing unit

Truth: Stable Resident has match 14 Cen Day in HU out of sample In-mover nonmatch Error Coded Stable resident nonmatch HU geocoded in wrong block Enumeration not found since items missing Stable resident nonmatch

15 Missing items can lead to problems in finding a match Census Joe Anders 40 Sue Anders 38 B. Anders 16 P-sample Joe Anders 40 Sue Anders 38 Bob Smith 17 Jim Smith 15 ? “B.” may be Bob, or Jim, or a 3 rd son

16 P-sample x (geocoding error) search area Census x (true) Geocoding error causes listing HU in the wrong block. Census enumerates in correct block. Match to census enumeration outside the search area is not found. P-sample person is coded nonmatch

17 Sources of errors Processing errors 2 studies evaluate 2010 CCM Data collection errors 4 studies evaluate for 2010 CCM

18 Info on processing error Matching Error Study All types of errors Administrative Records Study Types of error: ID enumeration, HU pop

19 Info on data collection error Respondent debriefings Types of error: HU pop, CenDay & IntDay usual residence Study of Missed Housing Units Type of error: geocoding

20 Info on data collection error Recall bias study Type of error: CenDay usual residence Comparison of census operations with CCM results Type of error: geocoding

21 Next steps Design estimators of E-sample & P-sample nonsampling errors For use in simulation study to synthesize errors Avoid double counting errors Continue to develop better understanding of error structure

22 U.S. Census Bureau