REPRESENTATIVE RESPONSE Some Examples ITSEW Peter Lundquist Statistics Sweden

Household Finances 2006 (HF) Design: Stratified network sample (18 years and older from RTP all household members are included) Sample size: households Mode: telephone (approx. 1/2 hour interview) Response rate: 69.6% Auxiliary variables are matched from external registers 2

HF: Estimated Mean Income Divided by Consumption Units 3 From Westling (2008)

HF: Comparison Between HT and GREG-estimators 4 From Westling (2008)

Living Condition Survey 2007 (LCS) Design: srs, 16 years and older from RTP Sample size: 7694 Mode: telephone (approx. 1 hour interview) Response rate: 73.4% Auxiliariy variables are matched from external registers Missing telephone-number for 3.7% of the sample 5

6 LCS: Response Rate Outcome RateNo. in Sample % Respondents Noncontacts Refusals Other nonresponse All

LCS: Auxiliary Variables Age Gender Country of Birth Marital Status Employment status Region Social allowance Type of housing estate Income Education Telephone (Sample based) 7

LCS: Major Reasons for Nonresponse Age [Refusal: years, Noncont: -34 years, Other:74+ years] Gender Country of Birth [Noncont and Other: born outside Sweden] Marital Status [Noncont: unmarried ] Employment status [Other: unemployed] Region [Noncont: living in big cities] Social allowance [Noncont and Other: if having allowance] Type of housing estate [Noncont: rented housing] Income [Noncont: no income Other: low income] Education [Nocont and Other: education code is missing] Telephone (Sample based) [Noncont: no phone] 8

LCS: Logit Model Response as Dependent 9 *) sign. level 10% **) sign. level 5% ***) sign. level 1%

LCS: Indicators 10 Based on estimated response probabilities under srs the following R-indicator (Schouten and Cobben 2007, 2008) is used and under srs the q 2 -indicator (Särndal and Lundström 2008) is

LCS: Indicators A measure of the estimated relative bias (in per cent) is computed by 11 As variables y k Sickness and activity allowance (yes/no), Income, Sickness pay (yes/no) and Employed (yes/no) are used to estimate the relative bias. All indicators computed for Resp5w and PCT100

LCS: R and q 2 Indicators for Response Before and After Follow-up 12

LCS: Conclusions The representativity doesn’t increase with the follow-up The indicators are estimates e.g. they are subject to variation (not computed) The same goes for the relative bias Active work with strategies for the group having social allowance and those with missing telephone Found auxiliary variables could be used in the creation of a new estimator 13

Labour Force Survey (LFS) Data from March-December 2007 Annual salary 2006 according to the Swedish Tax Register Process data from WinDati (CATI-system) 14. Supplemented with:

Response Rates for the Reference Weeks in a LFS Month (Means Based on LFS March-December 2007) 15.

Contact Days for the Reference Weeks in a LFS Month (Means Based on LFS March-December 2007) 16

Total Number Contact Days, Reference Weeks, in a LFS Month (Means Based on LFS March-December 2007) 17

Relative Bias for Income Accumulated on Contact Days, in a LFS Month (Means Based on LFS March-December 2007) 18

LFS: Final Variability in Relative Bias for Income, Reference Weeks (Means Based on LFS March-December 2007) Number of Observations Mean Relative Bias in Percent Low 95-Percent confidence interval High 95-Percent confidence interval Week Week Week Week Week All

20 HF 2006, LCS 2007 and LFS 2007: Estimated Relative Bias of mean Income in SEK in Percent and Outcome Rates HF 2006LCS 2007LFS 2007 Outcome Rate% Rel. Bias % of Sample* % Rel. Bias % of Sample % Rel. Bias % of Sample** Respondents Refusals Noncontacts + Other Nonresp *) Based on 36,864 individuals **) Based on the average of 10 months LFS (21,500 individual each month)

References Cobben, F. and Schouten, B. (2008). An empirical validation of R-indicators. Discussion paper 08006, CBS, Voorburg. Schouten, B. and Cobben, F. (2007). R-indexes for the comparison of different fieldwork strategies and data collection modes. Discussion paper 07002, CBS, Voorburg. Särndal, C.E. and Lundström, S. (2008). Assessing auxiliary vectors for control of nonresponse bias in the calibration estimator. Journal of Official Statistics, 24, Westling, S. (2008). “Utveckling för system av kontaktstrategier i intervjuundersökningar med individer och hushåll” Delrapport II, unpublished report, Örebro, Sweden: Statistics Sweden. [In Swedish] 21