Using administrative registers in sample surveys European Conference on Quality in Official Statistics 3-–6 May 2010 Kaja Sõstra Statistics Estonia

Kaja Sõstra Outline Administrative data are used during different stages of sample survey: establishing the survey frame sample design pre-filling of survey questionnaire calculating weights imputation small area estimation

Kaja Sõstra Examples of sample surveys and frames in Statistics Estonia Statistical unit SurveyFrame Person / household EU-SILC, LFS, HBSPopulation register Enterprise / establishment Wages and salaries, SBS, Information technology Statistical business register Agricultural holding Structure of agricultural holdings, Livestock production Statistical register of agricultural holdings

Kaja Sõstra Statistical registers Statistics Estonia has two main statistical registers based mainly on administrative sources: Statistical business register Commercial register Register of taxable persons other registers Statistical register of agricultural holdings Register of agricultural support and land parcels Register of taxable persons

Kaja Sõstra Sample design (1) Samples for surveys of economical units are selected every year in November Administrative data is used for – Stratification (economic activity, size class) – Sample allocation (turnover, number of employees) – Detection of outliers

Kaja Sõstra Sample selection (2) Samples for household surveys are selected in the end of each year by Population Register Statistics Estonia gives conditions for –establishing frame (age limits), –stratification (sex, age, place of residence), –sample size by stratas Sample is drawn using stratified systematic sampling Sample information is periodically updated by Population Register (deaths, migration)

Kaja Sõstra Problems with frames Lack of data for establishing correct frame –Immigrant population includes persons who´s parents were born abroad. Data about parents was missing for about 80% of persons –Data about institutions is missing Incorrect contact information in Population Register – incorrect addresses cause high nonresponse and increase cost of fieldwork

Kaja Sõstra Pre-filling of questionnaires New development in Statistics Estonia Decreases response burden, saves time of respondent Mainly the data from previous period of the same survey is used New developments for using administrative data: –annual bookkeeping reports for SBS from Commercial register –Data of agricultural support and land parcels

Kaja Sõstra Calculation weights Calculation weights consists of three steps Design weight Nonresponse adjustment weight Calibration weight Administrative data is used during all steps

Kaja Sõstra Nonresponse adjustment Nonresponse is increasing problem in household surveys Usually only administrative data is known for nonrespondents Response probability is estimated for every household or person Design weight is adjusted according to estimated response probability

Kaja Sõstra Response rates by age and sex % MaleFemale AverageHarju and Rapla county

Kaja Sõstra Population size and survey estimates by age group, males Thousand Population sizeEstimated number of persons

Kaja Sõstra Calibration Calibration of weights is a final step of weighting in all household surveys First trial to calibrate weights of agricultural survey has done Calibration groups in labour force survey: –Sex x 5-year age group (24 groups) –Place of residence (15 counties and capital) –Place of residence (urban, rural) –Nationality (Estonian, non-Estonian)

Kaja Sõstra Imputation Administrative data is used for cold-deck imputation Surveys of economic units: –VAT, social insurance, annual bookkeeping reports Household surveys –personal income tax for imputation income variables

Kaja Sõstra Conclusions Good quality of administrative registers is important to ensure quality of sample surveys There are plans to increase use of administrative data for sample surveys in Statistics Estonia –Establishing statistical population register –Pre-filling of questionnaires –Collecting part of data from registers Continuous development and updating administrative registers and cooperation is important for improving quality of all statistical activities

Kaja Sõstra Thank you for your attention!